US2464978A - Circuit integrity signaling means - Google Patents

Description

March 22, 1949. c. M. HINES CIRCUIT INTEGRITY SIGNALING IEANS z Sheets-Sheet 1 Filed NOV. 21, 1945 INVENTORV CLAUDE M HINES ATTORNEY March 22, 1949. c, HlNEs 2,464,978 I CIRCUIT INTEGRITY SIGNALING MEANS 3 Sheets-Sheet 2 Filed Nov, 21, 1945 8 1 5 6L" W. Na W mm u p m u OIL @M /N w L; H v A -W .\L H1 E 1 @NII 31 ATTORNEY March 22, 1949. c. M. HINES 2,464,978

CIRCUIT INTEGRITY SIGNALING MEANS Filed NOV. 21, 1945 3 Sheets-Sheet 3 INVENTOR CLAUDE M. HINES ATTORNEY Patented Mar. 22, 1949 CIRCUIT INTEGRITY SIGNALING MEANS Claude M. Hines, Verona, Pa., assignor to The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application November 21, 1945, Serial No. 830,077

15' Claims. (Cl. 177-311) This invention relates to circuit checkin means and has particular relation to apparatus for automatically signalling the integrity and the lack of integrity of control circuits such as the train wire circuits forming a part of electropneumatic brake control equipments for railway cars and trains.

Means for checking or signalling the integrity of control circuits have been heretofore proposed. Insofar as the train wire circuits of electropneumatic brake control systems for railway cars and trains is concerned, however, some of the checking and signalling systems heretofore proposed have been u1..luly complicated and unsuited to practical application while others have been exceptionally high in cost.

It is an object 01 my present invention to provide a circuit checking and signalling apparatus suited for practical application to control circuits of any type but particularly to train wire control circuits of electropneumatic brake control systems on railway cars and trains.

It is another object of my invention to provide a circuit checking and signalling apparatus of the type indicated in the foregoing object and characterized by signalling means located in the cab of a locomotive for readily and instantly apprising the engineer of the integrity and lack of integrity of the train wire circuits both while the brakes are released and during a brake application.

The manner of attainment of the above objects of my invention will be made apparent in the subsequent description thereof when read in. connection with the accompanying drawings wherein Figs. 1 and 2, taken together, constitute a diagrammatic view, showing one embodiment of the circuit checking and signalling apparatus constituting my invention applied to an electropneumatic brake control equipment for railway cars and trains, and

Fig. 3 is a fragmental diagrammatic view which, when taken in connection with Fig. 2. represents a modification of the checking and signalling equipment represented by Figs. 1 and 2.

Essentially the checking and signalling apparatus comprising my present invention includes a source of checking current which may be alternating current of a desired frequency, for ex ample 60 cycles, connected to one or more control circuits at one point, such as on the last car of a train, and checking current responsive re lays connected to corresponding control circuits located at another point, such as on the locomo- In another form 01 my invention two pairs of signal lamps, each pair having lamps of different colors respectively, are employed for each control circuit to be checked. One pair is employed for indicating integrity or lack of integrity of a particular control circuit while the brakes are released and the other pair is employed to indicate integrity or lack of integrity while the brakes are applied.

Description of equipment The checking and signalling apparatus comprising my present invention is applicable to any type of control circuits, the integrity or lack of integrity of which is desired to be detected. For purposes of illustration I have shown my invention in the drawings and will describe it hereinafter in connection with an electropneumatic brake control equipment for railway cars and go trains.

Before proceeding to a description of my invention, therefore, the essentials of the electropneumatic brake control equipment for railway cars and trains will be briefly described.

Referring to Figs. 1 and 2, the e1ectropneumatic brake control equipment comprises a plurality of train wires, shown as four in number and designated respectively by the reference numerals i, 2, 3 and I.

The wires i and 2 are connected through a suitable circuit-breaker I to a source of direct current represented by the storage battery 6. Battery 6 may be of any selected voltage, such as 32 or 64 volts. Circuit-breaker 5 is of the thermal-overload type which opens automatically in response to an abnormal or short-circuit current. The wire i is connected to the positive terminal of the battery 6 and will hereinafter be referred to as the positive battery wire while the wire 2 is connected to the negative terminal of the battery and will hereinafter be referred to as the negative battery wire or return wire.

The brake control equipment further comprises plurality of pairs of electro-magnet operated {valves 1 and 8. hereinafter referred to as the application magnet valve and the release magnet valve respectively.

For simplicity I have shown diagrammatically 'in the drawings, a pair of magnet valves 1 and 8 for the locomotive and a pair for each of two cars designated respectively, as Car A and Car B, the Car B being taken as the last car of a train and Car A representing the cars interposed between the last car of a train and the locomotive.

The magnet valves I and;8 are connected to the train wires, in the manner hereinafter to be more fully explained, so as to be controlled by a so-called master controller 9 which is a pneumatically operated manually controlled switch device of the self-lapping type having switch contacts for controlling energization and deenergization of the train wire circuits to which the magnet valves 1 and 8 are connected.

The master controller 9 is under the control of a brake valve operated by the engineer on the locomotive. Air under pressure for operating the master controller 9 is supplied from a storage reservoir II and a so-called supply pipe l2 connected to the reservoir l 1.

Each pair of magnet valves 1 and 8 controls the supply of fluid under pressure to a brake cylinder l3 and the release of fluid under pressure therefrom. Each brake cylinder is operative in the usual manner through suitable levers in response to the supply of fluid under pressure to the brake cylinder to cause application of the brake shoes to the tread of the car wheels with a corresponding force.

All of the brake cylinders l 3 are connected to a common train pipe [4, hereinafter called the straight-air pipe, so that the pressure established in all the brake cylinders is uniform. The straight-air pipe [4 is connected to the master controller 9 for a purpose hereinafter described.

A local reservoir, called the auxiliary reservoir I5, is provided on each of the cars and it is charged from-the supply pipe l2 through a oneway or check valve l6 which prevents back flow of fluid under pressure from the reservoir IS. The reservoirs l5 thus constitute local sources of fluid under pressure on each of the cars from which air is supplied to the brake cylinders under the control of the corresponding pair of magnet valves 1 and 8 on the same car. No auxiliary reservoir I5 is provided on the locomotive for the reason that the storage reservoir ll constitutes the source of fluid under pressure on the locomotive.

A so-called back-up switch I! is provided on the last car of the train, designated Car B, and is connected to the train wires I, 3 and 4 in a manner to control the magnet valves 1 and 3 on the locomotive and cars in a manner similar to that of the master controller 9. The purpose of the back-up switch is to enable a member of the engine crew on the last car of a train to control the brakes on the train under certain circumstances as when coupling cars to a train or when backing-up.

Considering the parts of the brake control equipment in further detail, each pair of magnet valves 1 and 8 may be embodied, as shown, in a single unit comprising a casing having two ports at the central portion thereof to which pipe connections are made. One of the ports is connected by a pipe l8 to the brake cylinder pipe l9 which in turn connects the brake cylinder and the straight-air pipe M. On the locomotive, the other port is connected by a pipe 20 to the supply pipe l2. On the cars; the other port is connected by a corresponding pipe 20 to the auxiliary reservoir l5 which is charged from the supply pipe 12 through another section of the pipe 20 including the check valve l6.

plied to the brake cylinder 13.

Each magnet valve 8 comprises a valve 24, of the poppet type, normally unseated by a coil spring and actuated to a seated position in response to energization' of a magnet winding 26. With the valve 24 unseated, communication is established past the valve from the pipe 18 to. atmosphere through an exhaust port. 21 thus venting fluid under pressure from the brake cylinder l3. With the valve 24 seated, the exhaust communication is closed.

The master controller 9 comprises a suitable casing having two flexible diaphragms 28 and 23 mounted therein in coaxially spaced relation and connected by a rigid stem 30. Stem 30 has a member 3|, of insulating material, fixed thereon and so arranged as to cause operation of two sets of switch contacts 32 and 33. As shown diagrammatically, each set of switch contacts 32 and 33 comprises two flexible contact fingers normally separated from each other, one of the contact fingers being longer than the other end engageable by the member 3| in a manner to be flexed or bent into engagement with the other contact finger upon a predetermined degree of axial movement of the stem 30 in the right-hand direction.

The two sets of switch contacts 32 and 33 are so disposed that in its traverse in the right-hand direction, the member 3| effects closing of the switch contacts 32 prior to closing of the switch contacts 33.

A spring biased stop 34 is contained in a recess 35 at one end of the casing and is adapted to be engaged by the right-hand end of the stem 30 to provide additional resistance to the movement of the stem between the time that the switch contacts 32 are closed and the time the contacts 33 are closed, thus providing stability of operation of the device and enabling closing of the switch contacts 32 without closing of the switch contacts 33.

Movement of the stem 30 and operation of the switch contacts 32 and 33 is effected and controlled by fluid pressure forces exerted in the chambers 36 and 31 on the outside faces of the two diaphragms 28 and 29 respectively. The chamber 36 is connected by a pipe 38 and branch pipe 39 to the brake' valve I 0 thereby enabling fluid under pressure to be supplied to the chamber 36 under the control of the brake valve in in the manner presently to be described.

The chamber 31 of the master controller 3 ils4 constantly connected to the straight-air pipe Brake valve I 0 is of the well known self-lapping type having an operating handle 40 which may be removably fixed on the outer end of a rotary operating shaft for operating suitable supply and release valve mechanisms. With the brake valve handle 43 in its normal or brake release position the brake valve establishes communication from the pipe 33 to an exhaust port and pipe 4i, thereby venting fluid under. pressure from the chamber 33 of the master controller 3. Upon operative rotation of the brake valve handle 43 out of its normal or brake release position into its so-called application zone, the valve mechanism of the brake valve is. operated to close oil the exhaust communication just described and establish a communication between the pipe I2 and the pipe 33, thereby causing fluid under pressure to be supplied from the reservoir II to the chamber 33.

The valve mechanism of the brake valve is such that the pressure of fluid delivered to cham; ber 33 is automatically limited to a value corresponding to the degree of displacement of the brake valve handle 43 out of its normal or brake release position. Thus, the greater the displacement of the brake valve handle from its brake release position, the greater is the pressure established in the chamber 33.

In operation, when the brake valve handle 43 is shifted from the brake release position into its application zone, the pressure established in the chamber 33 causes a shifting of the stem 33 in the right-hand direction to effect sequential closing of the switch contacts 32 and 33. The contacts 32 are effective, when'closed, to estab lish a connection from the positive battery wire i to wire 3, hereinafter called the release wire, thus causing energization of the magnet winding 23 of the release magnet valves 3 on the locomotive and on the cars. This circuit may be traced from the positive battery wire i by way of a wire 42, a wire 43, contacts 32 having an anti-arcing condenser '44 in parallel therewith, a wire 43, release wire 3, and thence in parallel through branch circuits on the locomotive and cars, each branch circuit comprising a branch wire 43, the magnet winding 26 of the release magnet valve 3, and a wire 41 to the return or negative battery wire 2.

With the magnet winding 23 of each release magnet valve 3 energized, the exhaust communication for each corresponding brake cylinder I3 is closed.

The contacts 33 are effective, when closed, to establish a circuit for energizing the magnet windings 23 of all of the application magnet valves 1 on the locomotive and cars. This circuit may be traced from the positive battery wire I by way of wire 42, contacts 33 having an anti-arcing condenser 43 in parallel therewith, a wire 43 to the train wire 4, hereinafter referred to as the application wire, and thence in parallel through branch circuits on the locomotive cars, each branch circuit comprising a wire 33, magnet winding 23 of the corresponding magnet valve I, and wire 41 to the return train wire 2.

With the magnet windings of both application and release magnet valves 1 and 3 energized, fluid under pressure is supplied to the brake cylinders l3 from the supply pipe l2 on the locomotive and from the auxiliary reservoirs II on the cars, the ultimate pressure established in the brake cylinders corresponding to that established in the chamber 33 in the master controller, as determined by the automatic operation of the master controller 3 in the manner presently to be described. As previously stated,

the brake cylinders II on the locomotive and cars are all connected to straight-air pipe l4 so that a uniform pressure is established therein. At the same time, the straight-air'pipe i4 is connected to the chamber 31 of the master con-. troller so that a fluid pressure corresponding to to urge thestem so in the left-hand direction sufllciently to effect the disengagement of the switch contacts 33. Opening of the contacts 33 interrupts the previously traced circuit for the magnet winding 23 of each application magnet valve 1 on the locomotive and on the cars thus causing the magnet windings.23 to be deenergized and the magnet valves I to be' operated to cut of! the further supply of fluid under pressure to the brake cylinders i3.

It will be apparent that ii the pressure of the fluid established in the chamber 33 of the master controller 3 is further increased, contacts 33 will again be closed and the magnet winding 23 of each magnet valve I reenergized to cause further fluid under pressure to be supplied to the brake cylinder l3 until such time as the corresponding pressure build-up in the chamber 31 of the master controller 9 is sufficient to restore the contacts 33 to open position, thereby terminating further supply of fluid under pressure to the brake cylinders.

Conversely, if the pressure in the master controller chamber 36 is reduced, the predominating force of the fluid pressure in the chamber 31 shifts the stem 30 sufliciently in the left-hand direction to efiect the opening of both of the sets of switch contacts 33 and 32, thereby deenergizing the magnet windings of both magnet valves 1 and 3 on the locomotive and cars. Fluid under pressure is accordingly released from each brake cylinder l3 under the control of the corresponding release magnet valve 8, until such time as a balance or substantial balance of fluid pressure forces in the chambers 36 and 31 is again reached, whereupon the stem 30 will be shifted sufficiently in the right-hand direction to effect reclosing of the contacts 32 and the consequent operation of the release magnet valve 3 to terminate further reduction of pressure in the brake cylinders.

When the brake valve handle 4|] is restored to its normal or brake release position and the pressure in the master controller chamber 36 thus reduced to atmospheric pressure, the pressure in the brake cylinders I3 is correspondingly reduced to atmospheric pressure and the brakes completely released.

While I have shown brake valve Ill as bein of the simple self-lapping type, it will be un derstood that in practice a combined automatic and straight-air type of brake valve such as shown and described in Patent No. 2,106,483 to E. E. Hewitt may be employed capable optionally of controlling the brakes either electro-pneumatically or solely by pneumatic control through the usual brake pipe.

The supply and the release of fluid under pressure to and from the brake cylinders l3 may be effected by the backup switch I! in a manner simulating that of the master controller 9. Essentially, the back-up switch ll comprises three stationary circumferentially spaced contact fingers, 52 and 53 connected to the train wires 3 and 4 by wires 54, 55 and 56 r'espec tively. A rotary contact drum of insulating material is operated by a suitable handle 58 and carries an arcuate contact segment 59 adapted to successively engage the contact fingers 5|, 52 and 53 in the order named upon rotation of the handle 58 in a clockwise direction, as seen in Fig. 2, out of a normal or release position into two other positions, designated respectively as lap and application" positions. In the lap position of the handle 58, the segment 59 connects the contact fingers 5| and 52 thereby connecting the train wire I to the train wire 3. It will be apparent that a circuit is thus established for energizing the magnet windin of the release magnet valve 8 on each car and on the locomotive.

When the handle 58 is further rotated in a clockwise direction to cause the segment 59 to engage all three contact fingers 5|, 52 and 53, positive battery wire I is connected to the train wire 4 as well as to the train wire 3, thus causing energization of the magnet windings of the application magnet valves 1 simultaneously with energization of the magnet windings of the release magnet valve 8. With the back-u switch handle 58 in its application position, therefore, fluid under pressure is supplied to the brake cylinders.|3.

When a pressure is established in the brake cylinders corresponding to the desired degree of brake application, the operator restores the back-up switch handle 58 to the lap position, thereby causing the segment 59 to separate from the contact finger 53 and efiect deenergization of the magnet windings of the application magnet valve 1 and resulting in termination of further supply of fluid under pressure to the brake cylinders while maintaining the release magnet valve windings energized to maintain the exhaust communications of the brake cylinders closed.

In order to minimize arcin at the contact fingers, two condensers 57 are provided, one connected across the contact fingers 5| and 52 and the other connected across the contact fingers 5| and 53.

It will be apparent, upon analysis, that it is highly important that the engineer on the 10- comotive be apprised in advance of the integrity and lack of integrity of the train Wire circuits, such as may result from breakage of any of the train wires, or a short-circuit between any two or more of the wires,because such faulty condition interferes with the proper control of the brakes on the train and under certain situations may prevent application of the brakes on the train. Thus, for example, if either the release wire 3 or the application wire 4 is broken, application of the brakes cannot be effected for the reason that breakage of the release wire 3 prevents energization of the release magnet valves 8 and breakage of the application wire 4 prevents energization of the application magnet valves 1. Similarly, a short-circuit between the release wire 3 and the return wire 2 or a short-circuit between the application wire 4 and the return wire 2 prevents energization of the release and application magnet valves 8 and 1 respectively.

The advantage of apprising the engineer of a train of a faulty condition of the train wire cir- I cuits will be apparent from the fact that if the faulty condition occurs while the, train is in motion the engineer may then resort to other brake controls available to him without the inherent delay occasioned by first resorting to the straight-air type of brake control. where the combination automatic and straightair type of brake valve is used. The engineer may, by a flick of his finger, condition the brake valve for automatic instead of straight-air operation. Likewise, if the faulty condition of the train circuits occurs while the train is stopped, the engineer may take immediate steps to have the faulty condition corrected.

According to my invention, the circuit checking and signalling apparatus disclosed herein, comprises a suitable source of alternating current on the last car of a train which, in Fig. 2 of the drawings is Car B. As shown in Fig. 2, the source of alternating current may consist of a source of direct current, such as a storage battery 60, connected through a suitable circuit breaker 6|, preferably of the thermal overload type, to the input terminals 62 and 63 of an inverter 64. The output frequency of alternating current at the output terminals 65 and 66 of the inverter may be any desired frequency such as, for example, 60 cycles. Similarly the output voltage of the inverter may be any selected value, such as forty volts.

One of the output terminals of the inverter 64, such as the terminal 65, is connected by a branch wire 61 to the return wire 2. The other output terminal 66 is connected by two branch Wires 68 and 69 to the release wire 3 and applica tion wire 4 respectively, with suitable condensers l0 interposed in the wires 68 and 69 to prevent the passage of direct current from the train wires through the inverter while permitting the passage of the alternating current from the inverter to the train wires.

The checking and signalling apparatus comprising one embodiment of my invention further comprises, as shown in Figure 1, a suitable panel board H on which are mounted a pair of relays l2 and 13 respectively, two asymmetric devices in the form of full-wave rectifiers 14 and 15 that may be of the dry disc type, two condensers 16 and 11, and four terminal posts I8, 19, 93 and 91. The terminal posts l8, l9, and 91 are connected by branch wires 80, 8| and 83 to the release wire 3, the application wire 4, and the return wire 2, respectively. The terminal post 93 is connected indirectly to th positive battery wire I by a wire 94 at the point of connection of the Wire I to the battery side of the switch contacts 32 of the master controller 9 so that the positive battery supply to the panel board II will be interrupted simultaneously with anypossible accidental severance of the positive battery supply to the switch contacts of the master controller. Such connection enables an instantaneous signal indication of the fault just mentioned to be effected, as will be explained more fully hereinafter.

The input terminals of rectifier l4 and the condenser 16 are connected in series relation between the terminal posts 78 and 91. Thus, one terminal of the condenser 16 is connected to the terminal post 18 and the other terminal of the condenser is connected to one input terminal of the rectifier 14. The other input terminal of the rectifier I4 is connected by a wire 82 to the terminal post 91.

For xample,

In a similar manner, the condenser 11 and input terminals of rectifier I are connected in series relation between the terminal posts 18 and 91. Thus, one terminal of the condenser 11 is connected to the terminal post 19 and the other terminal is connected to one input terminal of the rectifier 15. The other input terminal of the rectifier 15 is connected'by the wire 82 to terminal post 91.

The two relays 12 and 13 are identical in construction and are of standard type. Each relay comprises a suitable magnetic core having two windings 84 and 85 associated therewith, each effective upon energization to actuate an armature to effect closing of a normally open or front contact 86. Obviously, a relay having a single energizing coil may be employed with equal facility because for purposes of my present invention the two windings 84 and 85 of each of the relays 12 and 13 are connected in parallel and utilized as one winding.

The windings 84 and 85 are connected across the output terminals of the rectifier 14 and the windings 84 and 85 of the relay 13 are connected across the output terminals of the rectifier 15. Each rectifier 14 and 15 has a condenser 81 con nected across the output terminals thereof for smoothing out or minimizing the ripple in the direct current output of the rectifier to insure satisfactory operation of the relays 12 and 13,

Also mounted on the panel board 1| is a twocoil auxiliary relay 88, similar to the relays 12 and 13 except that it has two front contacts 88 and 98 and one back contact 9|, it being understood that the front contacts 89 and 98 are normally open and the back contact 9| normally closed. Each winding 84 and 85 of the relay has a condenser 92 connected in shunt relation thereto for imparting a delayed drop-out characteristic to the relay. the reason for which will be explained later.

The contacts 86 of the two relays 12 and 13 are arranged in series relation to jointly control energization of the lower winding 85 of the relay 88. This circuit may be traced from the position battery connected terminal post 93 on the panel board H by way of a wire 95 including the contacts 86 of the two relays 12 and 13 in series relation, winding 85 of the relay 88, a currentlimiting resistor 86, and wire 82 to th negative battery connected terminal post 81.

The winding 84 of the relay 88 functions as a holding or stick winding and is energized to maintain the contacts of the relay 88 picked-up, notwithstanding the interruption of the circuit for energizing th pick-up winding 85, in a manner hereinafter to be described. For the present it is deemed sufilcient to state that the winding 84 is so connected in a circuit extending from the terminal post 18 by way of a wire 98, front contact 89 of the relay 88, a wire 89, winding 84 of the relay 88, a current-limiting resistor I88, and wire 82 to the terminal post 91, that the winding 84 will be energized whenever contacts 32 of the master controller are closed to effect nergization of the windings of the release magnet valves 8.

Two signal lamps I8I and I82, preferably of different colors, such as green and red respectively, are also provided which may be mounted on the panel board 1I as shown, or on a separate base removed from the panel board. Th signal lamps I8I and W2 are respectively controlled by the contacts 98 and 9| of relay 88. Thus, the circuit for the signal lamp I8I extends from the terminal post 93 by way of a wire I83 including a current-limiting resistor I84, contact 88 in its pick-up or closed position, a wire I including the signal lamp I8I, to a wire I88 connected to the terminal post 91.

In a similar manner, the circuit of the signal lamp I82 extends from the terminal post 93 by way of the wire I83 including the current-limiting resistor I84, contact 9| in its closed or dropped-out position. a wire I81 including the signal lamp I82, and wire I88 to the terminal post 91.

Operation of checking and signalling system Let it be assumed that th switch BI is closed so that the inverter 84 is supplying alternating current output to the train wires 2, 3 and 4 and that the brakes on the train are released. In such case, the windings of the relay 12 are energized by the direct current output of rectifier 14 by reason of the alternating current input to the rectifier 14 supplied from the train wires 2 and 3. At th same time, the windings of the relay 13 are energized by the direct current output of the rectifier 15 due to the alternating current input to the rectifier 15 supplied from train wires 2 and 4.

With the windings of each of the two relays 12 and 13 thus energized, the contact 86 of each of the relays is actuated to its picked-up or closed position, the two contacts thereby jointly establishing a circuit for energizing the pick-up winding 85 of the relay 88. It will be apparent that since the terminal posts 93 and 91 are connected to the positive and negative battery wires I' and 2, respectively, at all times, the previously traced circuit on the panel board H for energizing pick-up winding 85 of relay 88 will be established on simultaneous closure of the contacts 88 of the two relays 12 and 13.

With the brakes released and the release and application wires 3 and 4 thus deenergized, it will be seen that actuation of the contact 89 of relay 88 to its picked-up or closed position is ineffectiv to establish a circuit for energizing the holding winding 84 because wire 3 is not energized.

Actuation of the contact 98 of relay 88 to its picked-up or closed position establishes a circuit for energizing the green signal lamp i8l, as will be apparent from the fact that closure of the contact 98 establishes the circuit, previously traced, from the terminal post 93 to the terminal post 91 by way of the signal lamp I8I, the two terminal posts 93 and 91 being connected respectively to the positive and negative batterywires I and 2.

The illumination of the green signal lamp I8I thus indicates to the engineer on the locomotive that the train wire circuits are in good condition and that no fault or break therein exists.

It will be seen that the actuation of the back contact 9I' of the relay 88 to its picked-up or open position interrupts the energizing circuit for the red signal lamp I82, thereby'extinguishing this lamp.

Now let it be further supposed that the train is put in motion and that the engineer subsequently effects an application of the brakes by operation of the brake valve I8. By reason of the energlzation of the magnet windings of the magnet valves 1 and 8 on the locomotive and cars in the manner previously described and the consequent saturation of the magnetic cores associated with these windings, the impedance of the magnet coils to the passage of alternating current from the 11 alternating checking current supplied over the wires 2, 3 and 4 is greatly reduced. An effective shunt connection is thus established across th input terminals of each oi the rectiflers I4 and I5. This results in such a reduction of the output current of the rectiflers I4 and I5 as to cause drop-out of the two relays I2 and I3.

With the brakes applied, as assumed, however, drop-out of the contacts of the two relays I2 and I3 does not eifect drop-out of the contacts of the relay 88 by reason of the energization of the holding winding 84 of the relay 88 which maintains the contacts of the relay 88 picked-up. When the brakes are applied, th release wire 3 is energized as will be apparent from previous explanation. Thus, not-withstanding the drop-out of the relays I2 and 13, the holding winding 84 of relay 88 is energized by way of the circuit extending from the positive battery wire I, through closed contacts 32 of the master controller 9, train wire 3, wire 80, terminal post I8, wire 98, contact 89 of relay 88, winding 84 of relay 88, resistor I00, wire 82 to the terminal post 81 and thence to the return or negative battery wire 2.

The purpose of the condenser 92 in shunt relation to the pick-up winding 85 of the relay 88 will now be apparent for it functions inherently by discharge thereof through the winding 85 to delay the drop-out of the contacts of the relay 88 responsively to the drop-out of the contacts of the relays I2 and I3 until such time as the current in the holding winding 84 has built-up sufficiently to maintain the contacts of the relay 88 in their picked-up positions.

Under the circumstances, therefore, the green signal lamp l0l continues to remain illuminated to indicate that no fault existed on the train wire circuits immediately prior to the application of the brakes.

It will be understood, that upon the restoration of the master controller 9 to its so-called lap position, that is the position in which the contacts 32 are closed and the contacts 33 are opened, in response to the build-up of the pressure in the brake cylinders to a degree corresponding to that of the control pressure established in the chamber 36 of the master controller, relay I3 will again be actuated to picked-up position by reason of the deenergization of the windings of the magnet valves 1 and the consequent removal of the low impedance shunt across the rectifier I5. So long as the windings of the several release magnet valves 8 remain energized, however, relay I2 will remain in its dropped-out position, thereby continuing to interrupt the circuit for energizing the pick-up winding 85 of the relay 88.

Now let it be supposed that the engineer effects a so-called graduated release of the brakes on the train, that is, a reduction in the degree of the brake application without completely releasing the brakes. In such case, both sets of switch contacts 32 and 33 of the master controller 9 will be opened during the interval of time that the pressure in the control chamber 36 is reducing and consequently the windings of all magnet valves I and 8 will be deenergized. Uipon opening of switch contacts 32 and the consequent deenergization of the release wire 3, the condenser 82 in shunt relation to the holding winding 84 functions to delay the drop-out of the contacts of relay 88 sufficiently to enable the two relays I2 and I3 to be simultaneously picked-up in response to the alternating checking current supplied over the train wires following upon deen- 12 ergization of the windings of magnet valves I and 8.

Thus, so long as the master controller contacts 32 remain in open position and, assiuning no fault or break occurring in the train wire circuits, the contacts of the relay 88 are maintained in their picked-up positions over the pick-up circuit including the series-connected contacts of the two relays I2 and 13.

When the pressure in the brake cylinders is reduced to that corresponding to the reduced pressure in the control chamber 38 of the master controller 3 and the contacts 32 are correspondingly reclosed, the circuit for the holding winding 84 of the relay 88 is again established. In this instance the condenser 92 in shunt relation to the pick-up winding 85 again functions to provide the delayed drop-out characteristic suflicient to enable the circuit for holding wniding 84 to be established notwithstanding the drop-out of the relay I2 in response to the reenergization of the windings of the release magnet valves 8.

It will be recalled from previous description that if no break in the train wires or no fault on the train wires occurs while the brakes are released, the two relays I2 and I3 are simultaneously picked-up to maintain the energizing circuit for the pick-up winding 85 of the relay 88, which in turn causes energization of the green signal lamp l0l. Let it now be assumed, however, that while the brakes are released, one or more of the train wires 2, 3 and 4 becomes severed at a point between the locomotive and the last car of the train. In such case, either one or both of the relays I2 and I3 is caused to drop out due to the interruption of the supply of the alternating checking current through the corresponding train wire circuit. As a result, the circuit for energizing the pick-up winding 85 of relay 88 is interrupted. Because the circuit for the holding winding 84 of relay 88 cannot be established while the brakes are released due to the fact that the release wire 3 is not energized, relay 88 will thus be restored to its dropped-out position following the expiration of the drop-out time of the relay. In the dropped-out position of relay 88, the contact interrupts the circuit for the green signal lamp l0! and the contact 8| establishes the circuit for the red signal lamp I02. Illumination of the red signal lamp thus results and indicates to the engineer that a fault or a break has occurred in the train wire circuits.

If a short circuit connection occurs between either one of the train Wires 3 or 4 and the return wire 2 while the brakes are released, one or the other of the two relays I2 and I3 is droppd-out due to shunting of one or the other of the rectifiers I4 or 15. In such case, therefore, the red signal lamp I02 is likewise caused to be energized. It will be understood that breakage of wires 2, 3 and 4 or the occurrence of a shortcircuit between either of wires 3 or 4 and return wire 2 is a serious condition for under such circumstances it is impossible to effect application of the brakes on the train by straight-air operation. If, however, the engineer is apprised by the illumination of the red signal lamp I02 of such serious condition he may resort to other brake control means available to him on the locomotive. For example, assuming a combination automatic and straight-air type of brake valve, the engineer may resort to automatic control of the brakes. Undesirable delay in initiating a brake application is thus prevented.

In the event that a break in train wires 2. 3

and 4 at a. point between the locomotive and the last car of the train occurs while an application of the brakes is in effect, no change from the normal signal indication, that of the green signal lamp HII energized, is effected. It will be seen that such is the case because due to energization of the train wire 3, the holding circuit for the holding winding 84 of relay 88 is maintained, thus maintaining the relay 88 in its picked-up position. However, upon the subsequent release of the brakes and the consequent deenergization oi the train wire 3, relay 88 will be dropped-out if the break in any of the train wires 2, 3 or 4 still continues.

If a short-circuit connection between the release wire 3 and the return wire 2 occurs while a brake application is in effect, the circuit breaker 5 connecting the battery 6 to the train wires I and 2 will be automatically opened due to the abnormal short-circuit current thereby produced. As a result. the battery supply to the master controller 9 is interrupted and consequently the magnet valves 1 and 8 on the locomotive and all the cars will be deenergized, thus effecting a release of the brakes on the train. This serious condition is indicated at once by simultaneous extinguishment of both signal lamps l8! and I82 due to the interruption of battery supply to the panel board ll simultaneously resulting from the opening of the circuit breaker 5.

The same result will occur in a short-circuit connection between the application wire 4 and the return wire 2 occurs at a time when a brake application is being initiated and the master controller switch contacts 33 are in closed position connecting the positive battery wire I to the application wire 4. If a short-circuit connection between the application wire 4 and the return wire 2 occurs during a brake application while the master controller 9 is in lap condition wherein the switch contacts 33 are opened and disconnect the positive battery wire I from the application wire 4, the green signal lamp l8l will remain energized and no change of signal indication will occur. It will be apparent that such is the case because notwithstanding the shunting of the rectifier i5 and the consequent drop-out of the relay 13, a holding circuit for the holding winding 84 of the relay 88 is maintained due to the energization of the release train wire 3.

If a short-circuit connection occurs between the positive and negative battery wires l and 2,

either while the brakes are released or while a brake application is in effect, circuit breaker 5 will be automatically opened in response to the abnormal short-circuit current, thereby disconnecting the train wires l and 2 from the battery 6 and rendering the master controller 8 ineffective to control the magnet valves 1 and 8. Due to the deenergization of magnet valves 1 and 8 as thus effected, the brakes will be released if they are already applied, or if the fault occurs while the brakes are released it will be impossible to effect application of the brake by straight-air operation. This condition is indicated by the simultaneous extinguishment of both signal lamps llll and I02, following upon interruption of the battery supply to the panel board II as a result of the opening of the circuit breaker 5. In either case, the engineer may resort to other brake controls at his disposal without delay, because he is apprised immediately of the occurrence of the fault.

The reason for connecting the terminal post 83 on the panel board H directly to the battery side of the switch contacts 32 of the master controller 9 by the wire 94 should now be apparent for the reason that failure of battery supply to the master controller 9 for any reason will instantly result in interruption of the battery supply to the panel board H and the consequent extinguishment of the two signal lamps Illl and I82. Thus, if the connection between the battery side of the switch contacts/ 0f the master controller 9 and the positive battery wire I established by the wires 42 and 43 becomes accidentally severed, the two signal lamps l0! and I 02 areinstantly extinguished to indicate this serious condition.

If a short-circuit connection between the release train wire 3 and the application train wire 4 occurs while the brakes are released, the green signal lamp I8l will nevertheless continue to remain energized notwithstanding the occurrence of this particular fault. This is so because the alternating checking current supplied from the inverter 64 on the last car of the train is still effective to maintain the two relays "i2 and i3 picked-up. No practical reason exists, however. for indicating such a fault at such time for the reason that the magnet valves I and 8 are not immediately affected. Moreover this fault condition is not one which is capable of serious or dangerous consequences.

If a short-circuit connection between the train wires 3 and 4 exists at the time a brake application is initiated or if it occurs during a brake application, the green signal lamp llll is not immediately deenergized or extinguished for the reason that the relay 88 is maintained in its picked-up position, notwithstanding the drop-out of the two relays l2 and 13, by reason of the holding circuit therefor previously described. However, the continued energization of the windings of both magnet valves 1 and 8 results in a so-called overcasting, that is a build-up of pressure in the brake cylinders l3 to a degree exceeding the pressure established in the control chamber 36 of the master controller 9. The higher force exerted on the diaphragm 29 with respect to that exerted on the diaphragm 28 correspondingly results in shifting of the contact stem 38 in the left-hand direction to effect opening of both sets of contacts 32 and 33, thereby causing simultaneous deenergization of the windings of all of the magnet valves 1 and 8. A rapid reduction of the pressure in the brake cylinders is thus produced and such reduction continues until the pressure in the brake cylinders and correspondingly in the chamber 3! of the master controller 9 is again reduced slightly below that in the control chamber 36, whereupon the contacts 32 will again be closed. Due to the short-circuit connection between the train wires 3 and 4, the windings of the magnet valves 1 and 8 will thus again be simultaneously energized to again cause overcasting or excessive pressure build-up in the brake cylinders.

Such repeated alternate increases and decreases in the degree of application of the brakes, sometimes referred to as pumping of the brakes, will of course be sensed by the engineer or members of the train crew and inherently serves as an indication of this particular faulty condition. Pumping of the brakes is not 9. dangerous condition and specific signal indication of this condition is not essential.

It will be observed that no change from the green signal lamp indication is effected as a result of the pumping action of the brakes as just described. This is so because, notwithstanding the opening of the switch contacts 32 of the master controller 9 in response to the overcasting and consequent interruption of the holding sircuit for the relay 88, the relays l2 and 13 are picked-up in response to the alternating checking current supplied over the train wires while both sets of contacts 32 and 33 of the master controller 9 are open. Thus, as in the case of a graduated release of the brakes previously described, pick-up winding 85 of the relay 88 is energized during the interval that the holding circuit for the relay 88 is interrupted. The relay 88 is thus not dropped-out during the pumping action of the brakes and consequently the green signal lamp remains energized.

If a short-circuit connection occurs between release wire 3 and the positive battery wire I while the brakes are released the consequent energization of the windings of the release magnet valve 8 will have no serious effect, insofar as brake control is concerned, except as continued energizati-on of the windings of the magnet valves 8 constitutes an undesired consumption of energy from the battery 6. It will be apparent that a short-circuit connection between the wires 3 and I will not effect deenergization or extinguishment of the normally energized green signal lamp lfll. This is so because, although the relay I2 is caused to drop-out in response to energizati-on'of the windings of the release magnet valves 8, the holding circuit of the relay 88 is established due to energization of the train wire 3 and consequently the relay 88 is not restored to its dropped-out position .to extinguish green signal lamp l].

Notwithstanding the existence of a short-circuit connection between the train wires I and 3 at the time abrake application is initiated, no change from the normal signal indication, that is energization of the green signal lamp Hll, is effected by initiation of the brake application. This is so because of the continued maintenance of .the holding circuit for the relay 88 due to the continued energization of the release train wire 3.

It wil be understood that the existence of a short-circuit connection between the train wires I and 3 does not interfere with the application of the brakes under the control of the master controller 9 except when it is desired to reduce the the degree of application of the brakes or to effect a complete release of the brakes. In such case, the continued energization of the windings of the release magnet valves 8 prevents the venting of fluid under pressure from the brake cylinders l3. If, however, the engineer attempts to release the brakes by operation of the brake valve I0 and finds that he cannot do so, such fact will be indicative of the short-circuit connection between train wires l and 3. The fact, therefore, that no signal indication is given of this particular fault condition is of no serious consequence. Obviously since the train has been brought to a stop safely in response to application of the brakes, opportunity is afiorded the crew of the train either to ascertain and remove the fault condition or circuit breaker may be manually operated to open position to effect the release of the brakes to enable the train to proceed temporarily until such time as th location of the fault can be ascertained and the fault corrected. In such case, the brakes on the train may be operated and controlled by the engineer using other brake controls at his disposal on the locomotive.

If a short-circuit connection accidentally occurs between the application wire 4 and the positive battery wire I while the brakes are released, the windings of the application magnet valves I will be continuously energized. Fluid under pressure will thus be supplied to the brake cylinders under the control of the application magnet valves 7 while fluid under pressure is released from the brake cylinders under the control of the deenergized release magnet valves 8. Such release of fluid under pressure from the brake cylinders is accompanied by a characteristic sound which may in itself serve to indicate this particular fault condition to the engineer or some member of the train crew. However the engineer is directly apprisedof this particular fault condition by extinguishment of the green signal lamp IM and illumination of the red signal lamp I02. This results from the fact that energization of the windings of the magnet valves 1 causes dropout of the relay I3 and the consequent deenergization of the pick-up winding of the relay 88 without a corresponding simultaneous establishment of the circuit for energizing the holding winding 84 of the relay 88, due to the fact that the train wire 3 is not energized. The relay 88 is accordingly restored to its dropped-out position in which the red signal lamp I92 is energized and the green signal lamp ml is deenergized.

If an accidental short-circuit connection occurs between the application wire 4 and the positive battery wire while an application of the brakes is in effect, the continued maintenance of energization of the windings of the application magnet valves 1 will cause overcasting and a resultant pumping action of the brakes. In this instance, the pumping action of the brakes is accompanied by a change in signal indication, that is, deenergization of the green signal lamp l0! and energization of the red signal lamp I82 following upon separation of the switch contacts 32 of the master controller 9 incidental to the overcasting. Due to the fact that the windings of the, application magnet valves 1 remain energized, the relay 13 remains in its dropped-out position. Thus when the switch contacts 32 of the master controller 9 are opened incidental to the overcasting, the circuit for energizing the holding winding 84 of the relay 88 is interrupted and since the contacts 32 will be opened for a. time longer than the drop-out time of the relay 88, without an accompanying establishment of the energizing'circuits of the pick-up winding 85 due to the continued drop-out of the relay l3, relay 88 will be restored to its dropped-out position thereby extinguishing the green signal lamp l0! and effecting illumination of the red signal lamp I02. The red signal lamp indication will continue thereafter until the particular fault condition is removed, due to the fact that reclosing of the switch contacts 32 of the master controller 9 incidental to the pumping operation of the brakes and the consequent reenergization of the release train wire 3 is not effective to establish the circuit for the holding winding 84 of the relay 88.

No signal indication is given in the event that a break in the positive battery wire I occurs. There is, as a matter of fact, no necessity for an indication of this particular fault condition for the reason that control of the magnet valves by the master controller 9 is not interfered with in such case. The only disadvantage resulting from breakage of the positive battery wire is that it renders the back-up switch l1 ineffective to control the magnet valves 1 and 8. This is of no serious consequence since as a matter of practice, a member of the train or yard crew who might utilize the back-up switch I! will, in accordance with customary practice, make a test application of the brake switch Prior to actual occasion for the use thereof. If, however, it should be de- .and inexpensive checking and signalling apparatus as is possible, I prefer to omit. such means for checking the battery wire I although it may be provided if desired.

It will thus be seen that the checking and signalling equipment shown in Figures 1 and 2 provides a simple, practical and adequate means for apprising the engineer of a break or fault condition on the train wire circuits which might seriously affect the control of the brakes. While; certain fault conditions or breaks in the train wire circuits are not indicated by the signal equipment, such conditions are not such as to result in a serious deficiency of brake control. Moreover, such instances of fault conditions in a train wire circuit are for the most part accompanied by characteristic symptoms of brake control deflciencies which may be sensed or detected by the engineer or members of the train crew without the necessity of the actual signal lamp indication.

Figure 3 Figure 3 shows a modification of the portion of the checking and signalling equipment provided on the locomotive in Figure 1. Only so much of the equipment in Fig. 3 will be described as differs from the equipment shown in Fig. 1, and like parts in the two equipments will be identified by the same reference numerals without further description in connection with the embodiment of Fig. 3. The embodiment in Fig. 3 differs from that in Fig. 1 in having two relays I12 and I13, corresponding in function to the two relays 12 and 13, but responsive directly to the alternating checking voltage supplied over the train wire circuits from the inverter 64 on the last car, or Car B, of the train, without rectification of such current. The need for rectifiers, corresponding to the rectifiers 14 and 15 in Figure 1, is thus eliminated and the windings of the v two relays I12 and I13 are connected directly across the train wires 2 and 3, and 2 and 4 respec-- tively. In order to prevent the passage of direct current employed for brake control purposes from affecting the windings of these two relays, condensers I16 and I11 that correspond to the condensers 16 and 11 in Figure l, are interposed in the connection between the windings of the relays and the train wires.

The relays I12 and I13 are identical in construction, each having a change-over contact alternatively positioned in one or the other of two circuit-closing positions depending upon whether the winding of the relay is energized or deenergized. For convenience of description the change-over contact of the relay I12 is designated by the reference numeral III and that of the relay I13 is designated by the reference numeral H2.

The change-over contact III ofrelay I12 is effective in its dropped-out position to establish a circuit for energizing one or the other of two signal lamps II! and Ill which are preferably of the same color, such as red, although they may be of different colors. Selection of the particular signal lamp energized is effected under the control of a pneumatic pressure operated switch device I2I which will be more fully described presently. I

In a similar manner, the change-over contact,

II2 of the relay Ill is efiective in its dropped-out position to establish alternatively an energizing circuit for either of two signal lamps I I5 and H6 depending upon the position of the pressure switch I2I. \The signal lamps H5 and H6 are preferably of the same, such as red, but they may be of different colors.

In its picked-up position, the change-over contact III of the relay I12 establishes a circuit for energizing either one of two signal lamps H1 and II8, depending upon the position of the pressure switch I2I. In a similar manner, the change-over contact II2 of the relay I13 is effective in its picked-up position to establish an energizing circuit for either one of two signal lamps H9 and I20, depending upon the position of the pressure switch I2I.

The signal lamps H1, H8, H9 and I20 may be of different colors respectively or different combinations of colors but they are preferably all of the same color, such as green.

The pressure switch I2I is preferably of the snap-acting type, having a movable contact I22 that is actuated from one position to a different position in response to an actuating fluid pressure supplied to the switch device exceeding a certain low value, such as five pounds per square inch. In the said one or normal position, the contact I22 bridges a pair of contacts I23 while in the different position the contact I22 bridges a different pair of contacts I24.

As indicated in Figure 3, the pressure chamber of the pressure switch I2I is connected by a branch pipe I25 to the pipe 38 leading to the control chamber 36 of the master controller 9.

. It will be apparent, therefore, that with the brake valve handle 40 in its normal or brake release position and the pressure in the control chamber 36 of the master controller 9 correspondingly at atmospheric pressure, the contact I22 of the pressure switch I2I will be in its upper position engaging the contacts I23. It will be further apparent that when the brake valve handle 40 is shifted out of its brake release position into the application zone to eifect the build-up of pressure in the control chamber 36 of the master controller to initiate a brake application, contact I22 will be shifted into engagement with the pair of contacts I24 by reason of the pressure in the control chamber 36 building-up above the five pounds per square inch pressure required to actuate the contact I22 of the pressure switch I2 I.

In operation, assuming that the brakes are released in the train and that a checking current it being supplied over the train wires by the inverter 64 on the last car of the train, the changeover contacts of the two relays I12 and I13 will be actuated to their respective picked-up positions if no fault or break in the train wire circuits exists. In such case, therefore, the two green signal lamps H1 and II 9 are illuminated or energized. The circuit for energizing the signal lamp Ill may be traced from the positive battery wire I by way of wires 42 and 43 to the point of connection with the switch contacts 32 of the master controller, thence by way of a wire I26, change-over contact III of th relay I12, a

wire I21 including signal lamp H1, and a wire I23 including the pressure switch contacts I23 and I22 to the return or negative battery wire 2.

The circuit for energizing the signal lamp H9 may be traced from the positive battery wire I by way of the wires 42, 43 and I26, change-over contact H2 of relay I13, a wire I29 including the signal lamp H9 to the wire I28, and thence by way of the contacts I23 and I22 of the pressure switch I2I to the negative battery wire 2.

It will thus be seen that so long\ as no fault or break exists in the train wires while the brakes are released, the two green signal lamps H1 and H9 will be energized.

With no fault or break existing in the train wire circuits, application of the brakes produces a change in the signal indication, that is, the signal lamps H1 and H9 are deenergized while signal lamp H4 and either one of signal lamps H6 or I20 are energized, dependent upon the switch contacts 33 of the master controller 9 being in closed or open position respectively.

It will be understood that with both sets of switch contacts 32 and 33 of the master controller 9 closed in response to initiation of the brake application, the windings of the magnet valves 1 and 8 are all energized and consequently due to the lowimpedanceshunt provided by the windings of the magnet Valves across the windings .of the relays I12 and I13, the relays are caused to dropout. At the same time, the contact I22 of the pressure switch I2I..is actuated into engagement with the contacts I24 and out of engagement with the contacts I23.

With the change-over contact III of relay I12 in its dropped-out position, a circuit is established for enregizing the signal lamp H4, this circuit extending from the positive battery wire I by way of the Wires 42, 43 and I26, changeover contact III, wire I32 including the signal lamp H4 to the wire- I33, and thence by way of the contacts I24 and I22 of the pressure switch I2I to the return wire 2.

With the change-over contact H2 of relay I13 in its dropped-out position, the circuit for signal lamp H6 is established from the positive battery wire by way of the wires 42, 43 and I26, changeover contact H2, wire I34 including the signal lamp H6, to the wire I33, and thence by way of the contacts I24 and I22 of the pressure switch I2 I to the return wire 2.

When the master controller 9 is operated to open switch contacts 33 but not the switch contacts 32 in response to the build-up of pressure in the brake cylinders to a degree corresponding to that established in the control chamber 36 of the master controller, the windings of the application magnet valves 1 are correspondingly deenergized while the windings of the release magnet valves 8 remain energized. The consequent removal of the low-impedance shunt around the winding of the relay I13 results in pick-up of the relay in response to the alternating checking current supplied from the inverter 64. Thus, with the change-over contact H2 of relay I13 in its picked-up position at this time, the circuit for energizing the signal lamp I20 is established, this circuit extending from the positive battery wire I by way of the wires 42, 43 and I26, change-over contact H2, wire I35 including the signal lamp I20, the wire I33, and thence by way of the contacts I24 and I22 of the pressure switch I2I to the return wire 2.

So long as the master controller 9 remains in this condition, which will be referred to as the as just described, the opening of the switch contacts 32 of the master controller 9 occurring while the pressure in the brake cylinders is reducing to the reduced pressure established in the control chamber 36 of the master controller 9, the consequent deenergization of the windings oi the release magnet valves 8 causes a removal of the lowimpedance shunt across the windings of the relay I12. Change-over contact III of relay I12 is thus again actuated to its picked-up position in response to the energization of the winding of relay I12 by the alternating checking current supplied from the inverter 64. Under these circumstances, therefore, signal lamp H8 is energized by reason of the circuit therefor extending from the positive battery wire I by way 01' the wires 42, 43 and -I26,'change-over contact III, wire I36 including the signal lamp H8, and wire I33 including the switch contacts I24 and I22, to the return wire 2.

Thus, the simultaneous energization of the two green signal lamps H8 and I20 indicates to the engineer that both sets of switch contacts of the master controller 9 are in open position during the graduated release of the brakes.

When the switch contacts 32 of the master controller 9 are reclosed at the time that the pressure in the brake cylinders is reduced substantially to or slightly below that established in the control chamber 36 of the master controller 9, the change-over contact III of relay I12 is again restored to its dropped-out position establishing the energizing circuit for the signal lamp H4.

After a train has been brought to a stop in response to an application of the brakes and the engineer effects a release of the brakes prior to again starting the train, signal lamps H1 and H9 are again energized and signal lamps H4, H6, H3 and I20 are all deenergized due to the restoration of the contact I22 of the pressure switch I2I back into engagement with the contacts I23.

If, while the brakes on the train are released a break in any of the train wires 2, 3, and 4 occurs, or a short-circuit connection between either of the wires 3 or 4 and the return wire 2 occurs, or a short-circuit connection between either of the wires 3 or 4 and the positive battery wire I occurs, a change in signal indication is efiected.

It will be apparent that with the brakesreleased, breakage of the train wire 3 will cause relay I 12 to drop out, thereby efiecting deenergization of the signal lamp H1 and energization of the signal lamp I I3. The circuit for the signal lamp H3 is similar to that for the signal lamp H1 in that, with the change-over contact III 21 the wire I23 to the wire I23 through the signal lamp Ill instead of throughthe signal lamp II3.

Obviously, if both oi the train wires 3 and 4 are simultaneously broken, or if the train wire 2 alone is broken, both relays I12 and I13 are simultaneously dropped-out and both signal lamps I I3 and III are simultaneously energized.

A short-circuit connection occurring between the release train wire 3 and the return wire -2 causes shunting of the winding of the relay I12 and 'a consequent drop-out thereof Just as in the case of breakage of the release train wire 3, the red signal lamp II3 being correspondingly ener- A short-circuit connection between the application train wire 4 and the return wire 2 establishes a shunt around the winding of the relay I13, resulting in drop-out thereof and consequent energization of the red signal lamp HE.

A short-circuit connection between the positive battery wire I and the release wire 3, while the brakes are released, causes energization of the windings of the release magnet valves 3 and, for reasons hereinbefore explained, a corresponding drop-out of the relay I12 to effect energization of the red signal lamp I I3. A short-circuit connection between the positive battery wire I and the application wire 4, while the brakes are released, causes energization of the windings of the application magnet valves 1 and a consequent dropout of the relay I13, resulting in energization of the red signal lamp II5.

A short-circuit connection occurring between the release wire 3 and the application wire 4,

while the brakes are released, does not produce any change in signal indication for the reason that the relays I12 and I13 continue to he pickedup in response to the alternating checking current, notwithitanding the connection between the wires 3 and 4.

A short-circuit connection between the positive battery wire I and the return wire 2, while the brakes are released, results in extinguishment of all signal lamps. The reason for such result should be apparent from the description in connection with the first embodiment, for such shortcircuit connection causes automatic opening of the circuit breaker to di connect the battery train wires I and 2 from the battery 6. With the battery supply to the signal lamps thus entirely cut 01!, all of the signal lamps are correspondingly deenergized.

It will be apparent that, with the brakes applied, a short-circuit connection between the wires I and 2 will likewise result in extinguishment of all signal lamps, by reason of the opening of circuit breaker 5.

In the event that the battery supply to the master controller 3 is interrupted for any reason, such as breakage of either one or both of the wires 42 and 43, the battery supply to all of the signal lamps is correspondingly interrupted and all of the lamps are, extinguished. In this respect, therefore, the present embodiment functions identically to that of the first described embodiment.

Upon application of the brakes, with no faults or breaks in the train wire circuits, the signal lamps H4 and H6 or I will be energized, as previously described.

If release wire 3 alone is severed during a brake application, signal lamp II4 remains energized, that is, no change in signal indication occurs by reason of the fact that relay I12 is already dropped-out due to the low-impedance shunt cacao-re existing across it as a result of energization of the windings of release magnet valves 3.

If application wire 4 alone is severed during a brake application relay I13 will drop out; if not already dropped out due to energization of the windings of application magnet valves 1 and the consequent existence of a low-impedance shunt across the winding of relay I13. Thus, if relay I13 is picked-up at thetime the application wire the return wire 2, the short-circuit connection thus made between the positive train wire I and the return wire 2 causes automatic opening of the circuit breaker 5 and a consequent extinguishment of all signal lamps. The same result is produced if a short-circuit connection occurs between the application wire 4 and the return wire 2, while the application wire 4 is energized by way of the switch contacts 33 of the master controller 9. If a short-circuit connection between appli cation wire 4 and return wire 2 occurs after switch contacts 33 open during an application of the brakes in response to build-up of brake cylinder pressure, such short-circuit connection between the wires 4 and 2 will shunt the winding of the relay I13 to cause drop-out thereof, thus resulting in the energization of the signal lamp I I6 and de-- energization of the signal lamp I20.

If a short-circuit connection between the application wire 4 ancl the release wire 3 occurs during a brake application, overcasting and pumping operation of the brakes will occur, the same as previously described in connection with the first embqdiment. In such case, the alternate opening and'closing of the switch contacts 32 and 33 of the master controller 9 will result in alternate pick-up and drop-out of the relays I12 and I13 with a consequent change in the signal indication on the lamps. H4, H6, H8 and I20, depending upon whether the relays are picked-up or dropped-out.

If a short-circuit connection occurs between the positive battery wire I and the release wire 3, while the brakes are applied, no change in signal indication occurs for the reason that such connection only shunts the already closed switch contacts 32 of the master controller 9 with no effect on the relay I12 'difierent from that already produced in response to energization of the windings of the magnet valves 8. However, as pointed out above in connection with the first described embodiment, such a short-circuit condition prevents the release of the brakes which inherently indicates the character of the fault to the engineer or member of the train crew.

If a short-circuit connection occurs between the positive battery wire I and the application wire 4 during an application of the brakes, overcasting and a consequent pumping action of the brakes results. In this instance, the winding of the relay I13 remains shunted due to the continued energization of the windings of the application magnet valves 1. Thus relay I13 remains permanently dropped-out causing the signal lamp angers 23 H8 to be continuously energized. Due to the alternate opening and closing of the switch contacts 32 of the master controller 9, incidental to the pumping operation of the brakes, the relay I12 is alternately picked-up and dropped-out to cause the signal lamps vI l4 and H8 to be alternately energized. A characteristic signal indication is thus given for this particular fault condition.

It will thus be apparent that in the embodiment of my invention disclosed in Figures 2 and 3, the engineer is apprised at all times, both while the brakes are released and while the brakes are applied as to the integrity or lack of integrity of the train wire circuits by characteristic signal indication. In addition, the engineer is likewise apprised during a brake application of the operative conditionof the master controller 9 by characteristic signal indications.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. Apparatus for signalling the integrity and lack of integrity of a plurality of electrical circuits, said apparatus comprising a source of alternating voltage impressed at one corresponding point on each of said circuits, a plurality of relays each of which is operatively connected at another point to a corresponding one of the different circuits and operatively responsive only to the alternating current supplied from said source so long as the integrity of the corresponding circuit is not impaired, and signal means controlled by the cooperative action of all of said plurality of relays for indicating the integrity or lack of integrity of one or more of said circuits.

2. The combination with an electrical brake control circuit including a circuit breaker device that is automatically operated in response to an abnormal or short-circuit current in the circuit to an open position disconnecting the circuit from a source of operating voltage, of a source of alternating voltage impressed on said circuit at one point, electroresponsive means connected to said circuit at another point and operatively responsive only to alternating current supplied from said source for checking the integrity of the circuit, and signal means controlled by said electroresponsive means selectively to indicate the integrity or lack of integrity of the circuit, said signal means being supplied with energy from said source of operating voltage under the control of said circuit breaker whereby supply of energy to said signal devices is terminated simultaneously with the termination of supply of operating voltage to the control circuit by opening of said circuit breaker.

3. The combination with an electrical brake control circuit and a control device operative to effect the imposition of an operating voltage on said circuit, of a source of alternating current connected to said circuit at one point, an electrical relay connected to said circuit at another point and operatively responsive only to the alternating current supplied from said source, a signal device, and means providing a circuit under the control of said relay for energizing said signal device, said circuit-providing means being so arranged as to be interrupted whenever the said control device is disconnected accidentally or otherwise from the source of operating voltage.

4. For use in an electrical brake control equipment for railway cars and trains of the type having a plurality of train wires extending from car to car throughout the train, the combination of means on the last car or the train for impressing an alternating voltage across each of a plurality of pairs of said train wires, a plurality of electroresponsive means on the locomotive each of which is associatively connected to a corresponding difierent pair of train wires and operatively responsive to the alternating voltage supplied by said source so long as the integrity of the core responding pair of train wires is not impaired, and signal means controlled by the cooperative action of said plurality of electroresponsive means for indicating the integrity or lack of integrity of all of said train wires.

5. For use in an electrical brake control equipmentfor railway cars and trains of the type having a plurality of train wires extending from car to car throughout the train, the combination of means on the last car of the train for impressing an alternating voltage across each of a plurality of pairs of said train wires, a plurality of electroresponsive means on the locomotive each of which is associatively connected to a corresponding different pair of train wires and operatively responsive to the alternating voltage supplied by said source so long as the integrity of the corresponding pair of train wires is not impaired, and a pair of signal devices jointly controlled by said plurality of electroresponsive means in such a manner that one of said signal devices is operated so long as the integrity of all of said train wires is not impaired and the other of said signal devices is operated when the integrity of one or more of said train wires is impaired.

6. For use in an electrical brake control equipment for railway cars and trains of the type having a plurality of train wires extending from car to car throughout the train, the combination of means on the last car of the train for impressing an alternating voltage across each of a plurality of pairs of said train wires, a plurality of electroresponsive means on the locomotive each of which is associatively connected to a corresponding different pair of train wires and operatively responsive to the alternating voltage supplied by said source so long as the integrity of the corresponding pair of train wires is not impaired, a relay jointly controlled by said plurality of electroresponsive means in a manner to be picked-up so long as. all of said electroresponsive devices are operatively energized, and dropped-out when one or more of said electroresponsive means is deenergized, and a pair of signal devices one of which is operatively energized under the control of said relay only when said relay is in a picked-up position and the other of which is operatively energized only when said relay is in a dropped-out position.

'7. For use in an electrical brake control equipment for railway cars and trains of the type having a plurality of train wires extending from car to car throughout the train from the locomotive to the last car of the train and electroresponsive brake control means connected to said train wires and selectively energized and deenergized under the control of the operator on the locomotive to control the application and the release of the'brakes on the train, the combination of a source of alternating voltage connected to each of a plurality of pairs of said train wires on the last car of the train, a plurality of electroresponsive devices on the locomotive each of which devices is operatively connected to a corresponding pair of train wires and operatively responsive to the alternating current supplied by said source on the last car so long as the integrity oi the corresponding train wires is not impaired while the brakes on the train are released and at least ,one of which is operatively deenergized in response to application of the brakes by reason 01 energization of one of the electroresponsive brake control means during a brake application and the corresponding impedance effect produced thereby, a relay having a pick-up winding and a holding winding energization oi. either of which is effective to pick-up the relay and deenergization of both of which is effective to cause drop-out of the relay, said plurality of electroresponsive means cooperating jointly to effect energization of the pick-up winding of said relay so long as the integrity of the respective train wires is not impaired while the brakes are released, said relay being effective in its pickedup position to establish a circuit for energizing the holding winding of said relay when the brakes are applied to prevent drop-out of the relay notwithstanding operative deenergization of one or more of said electroresponsive means in response to application of the brakes, and a pair of signal devices one or which is operatively energized only while said relay is in its pickedup position and the other of which is operatively energized only while said relay is in its droppedout position.

8. For use in an electrical brake control equipment for railway cars and trains of the type having a plurality of train wires extending from car to car throughout the train from the locomotive to the last car of the train and electroresponsive brake control means connected to said train wires and selectively energized and deenergized under the control of the operator on the locomotive to control the application and the release of the brakes on the train, the combination 01' a source of alternating voltage connected to each of a plurality of pairs 01. said train wires on the last car of the train, a plurality of electroresponsive devices on the locomotive each of which devices is operatively connected to a corresponding pair of train wires and operat vely responsive to the alternating current supplied by said source'on the last car so long as the integrity of the corresponding train wires is not impaired while the brakes on the train are released and at least one of which is operatively deenergized in response to application of the brakes by reason of energization of one of the electroresponsive brake control means during a brake application and the corresponding impedance eil'ect produced thereby. a relay having a pick-up winding and a holding winding energization of either of which is eflective to pick up the relay and deenergization of both of which is effective to cause drop-out of the relay. said plurality of electroresponsive means cooperating jointly to eflect energization of the pick-up winding of said relay so long as the integrity of the respective train wires is not impaired while the brakes are released, means including a selfholding contact of said relay for establishing a connection of the holding winding of said relay to one pair of train wires whereby a self-holding circuit for energizingthe holding winding of the relay is established upon application of the brakes to prevent drop-out of the relay, means providing a delayed-action characteristic to said relay whereby to insure establishment o the selfholding circuit for energizing the holding winding of the relay notwithstanding operative deenergization of one or more of said electroresponsive means when the brakes are applied,

relay in such a manner that one 01 said signal' devices is energized only while the relay is in its picked-up position and the other 01' said signal devices is energized only while the relay is in its dropped-out position. I

9. For use in an electrical brake control equipment for railway cars and trains of the type having a plurality .of train wires extending from car to car throughout the train from the locomotive to the last car of the train and electroresponsive brake control means connected to said train wires and selectively energized and deenergized under the control of the operator on the locomotive to control the application and the release of the brakes on the train, the combination of a source of alternating voltage connected to each of a plurality of pairs of said train wires on the la-st car of the train, a plurality of electroresponsive devices on the locomotive each of which devices is operatively connected to a corresponding pair of train wires and operatively responsive to the alternating current supplied by said source on the last car so long as the integrity of the corresponding train wires is not impaired while the brakes on the train are released and at least one of which is operatively deenergized in response to application of the brakes by reason of energization of one of the electroresponsive brake control means during a brake application and the corresponding impedance eifect produced thereby, a relay having a pick-up winding and a holding winding energization of either of which is eilective to pick-up the relay and deenergization of both of which is effective to cause drop-out of the relay, said pluralitv of electroresponsive means cooperating jointly to effect energ zation of the pick-up winding of said relay so long as the integrity of the respective train wires is not impaired while the brakes are released. said relay being efiective in its pickedup position to establish a circuit for energiz ng the holding winding of said relay when the brakes are applied to prevent drop-out of the relay notwithstanding operative deenergization of one or more of said electrores onsive means in response to appl cation of the brakes. means for prov ding a dela ed-action characteristic to said relay whereby to revent a momentary drooout of said relay which might otherwise result due to initiation of a brake application or of a graduated release operation. and two signal devices contro led by said relay one of which is energ zed only so long as the said relay is pickedup and the other of wh ch isenergized only so long as said relay is in its dropped-out posit on.

10. For u e in an electrical brake control equipment for ra lway cars and trains of the type having a plurality of train wires. electroresponsive brake control means connected to the train wires and means under the control of the operator for selectively controlling the imposition of a'direct current voltage to said train wires for controlling energization and deenergization'of said electroresponsive brake control means, the combination of a source of alternatinq current on the last car of the train, means providing a connection from said source to one or more pairs of said train wires in a manner such that the said source is unaffected by the imposition of direct current voltage on said train wires, a plurality of elec-- trical relays on the locomotive, means for connecting each of said relays to a corresponding pair of train wires in such a manner that the relays are operatively responsive to the altemating current supplied by said source while being unaffected by a direct current control voltage imposed on said wires, a pair of signal devices, and an auxiliary relay controlled by the joint action of said two relays in a manner causing one of said signal devices to be energized only while the integrity of'said train wires is not impaired and the other of said signal devices to be energized only when-the integrity of one or more of said train wires is impaired.

11. Apparatus for signalling the integrity and lack of integrity of an electrical brake control circuit including a pair of train wires extending from car to car throughout the train from the locomotive to the last car and having electroresponsive brake control means connected to said pair of wires operative in response to a direct current voltage impressed on said wires under the control of the operator, said apparatus comprising the combination of a source of alternat ing voltage on the last car of the train connected to said pair of wires, an-alternating current responsive relay on the locomotive connected to said pair of train wires, said relay being operatively energized by the alternating current supplied from said source so long as the integrity of said pair of train wires is unimpaired and being operatively deenergized anddropped-out in response to impairment of the integrity of said pair of train wires as well as energization of said electroresponsive brake control means acting as a low impedance shunt whenever a brake application is efiected, switch means selectively operated to one or the other of two different positions depending upon whether the brakes on the train are applied or released, a first pair of signal devices jointly controlled by said relay and said switch device in such a manner as to be alternatively energized while the brakes are released depending upon said relay being picked-up or dropped-out and a second pair of signal devices jointly controlled by said relay and said switch device in such a manner during a brake application that one of said second pair of signal devices is energized only when said relay is picked-up and the other of which is energized only when the relay is dropped-out.

12. In an electrical brake control system for railway cars and trains of the type having a plurality of train wires, electroresponsive brake control means connected to said wires, and manually controlled switch means variously conditionable to selectively energize and deenergize the train wires and the electroresponsive brake control means to initiate an application or a release of 5 the brakes or to maintain a predetermined degree of brake application, the combination of a source of alternating voltage impressed on said train wires at one point, electroresponsive relay means connected to said train wires at another point and operatively responsive only to the alternating current supplied from said source and adapted to be operatively deenergized in response to the change in the impedance of the electroresponsive brake control means to the alternating current when said brake control means is energized under the control of said manually controlled switch means, switch means alternatively conditioned in one or the other of two different positions depending upon the brakes being applied or released, and two different signal means, said relay means and the last said switch means cooperating jointly in a manner to cause one of said signal means to be operative under the control of the relay means while the brakes are released to indicate the integrity or lack of integrity of the train wires and the other of said signal means being operative under the joint control of said relay means and said'last mentioned switch means when the brakes are applied to provide an indication of the operating condition of the, manually "'-'oon.- trolled switch means and also 01' the integrify and lack of integrity of the train wires.

13. Apparatus for signalling the integrity and lack of integrity of electropneumatic brake control circuits on railway cars and trains including a plurality of train wires extending throughout the train from car to car from the locomotive to the last car on the train and electroresponsive brake control means connected to said wires in a manner to be energized in response to the imposition of a direct current control voltage impressed thereon under the control of the operator, saidapparatus comprising a source of alternating voltage on the last car of the train, means for connecting said source to each of a plurality of difierent pairsof train wires in a manner to be unaffected by the direct current control voltage impressed on said wires, a plurality of electrical relays on the locomotive, means connecting said relays to corresponding pairs of said train wires in a manner to be unaffected by the direct current voltage impressed 0n the wires while being operatively responsive to the alternating voltage impressed thereon from said source, a plurality of pairs of signal devices for each of said relays and a switch device selectively operated to either one of two different positions depending upon the brakes on the train being applied or released, said relays and said switch device cooperating in such a manner as to cause one or the other of the signal devices of one pair to be energized while the brakes are released depending upon whether the relay is picked-up-or dropped-out, and as to cause one or the other of the signal devices of a different pair to be energized during a, brake application depending upon the relay being picked-up or dropped-out.

14. In an electrical brake control system for railway cars and trains of the type having a plurality of train wires, electroresponsive brake control means connected to said wires, and manually controlled switch means variously conditionable to selectively energize and deenergize the train wires and the electroresponsive brake control means to initiate an application or a release of the brakes or to maintain a predetermined degree of brake application, the combination of a source of alternating voltage on the last car of the train, means connecting said source to each of a plurality of pairs of said wires in a manner to render said source unaifected by energization of said wires under the control of the manually controlled switch means, a plurality of electroresponsive relay means on the locomotive of the train, means connecting each of said plurality of electroresponsive relay means to a corresponding diflerent pair of said train wires in a manner to be responsive to the alternating voltage impressed on the corresponding pair of wires from said source while being unaifected'by the energizing current supplied to said wires under the control of the manually controlled switch means except insofar as such energization involves a change in the characteristic impedance to the alternating current supplied 'by said source to said train wires, and signal means controlled by said electroresponsive means for indicating the integrity or lack oi. integrity of the train wires as well as the operative condition of the manually controlled switch means.

15. In combination, an electrical brake control circuit, a source of operating voltage, a circuit breaker device normally connecting said source to said circuit and automatically operated in response to an abnormal or shortcircuit current in the circuit to an open position disconnecting said circuit from said source of operating voltage, a source of alternating voltage impressed on said circuit at one point, electroresponsive means connected to said circuit at another point and operatively responsive only to alternating current supplied from said source of alternating voltage for checking the integrity of said circuit, and two signal devices alternatively and selectively energized under the control of said electroresponsive means by current supplied, in each case, from said source of operating voltage under the control of said circuit breaker in such manner that CLAUDE M. runes.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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