US2110960A - Automatic train control and signaling system - Google Patents

Description

March 15, 1938. c. MODQNALD 2,110,960

AUTOMATIC TRAIN CONTROL AND SIGNALING SYSTEM Filed Dec. 28, 1936 3 Sheets-Sheet 1 23m a \m wxuo'fi/ W i M March 15, 1938. J. c. MCDONALD 2,110,960

AUTOMATIC TRAIN CONTROL AND SIGNALING SYSTEM Filed Dec. 28. 1956 3 SheetsSheet 2 J l {9} Jaw/v C. Mwam AL March 15, 1938. J. c. M DONALD AUTOMATIC TRAIN CONTROL AND SIGNALING SYSTEM Filed Dec. 28, 1956 3 Sheets-Sheet 5 HHHHH BLOCK JOHN G M fiO/VA L D 2114 I fl M Patented Mar. 15, 1938 UNITED STATES AUTOMATIC TRAIN CONTROL AND SIGNAL- ING SYSTEM John 0. McDonald, New Yorlr, N. Y.

Application December 28, 1936, Serial No. 117,929

13 Claims.

My invention relates broadly to railway train control and signaling systems, and more particu larly to an improved block arrangement and method of operation.

One of the objects of my invention is to provide a dependable and efficient method of signaling and controlling the operation of railway trains in an extensive block system, with simplifled apparatus and circuit connections.

Another object of my invention is to provide a method of supplying alternating current to a track circuit whereby various lengths of track may be accommodated with no substantial change in the application or operation of the 16 system of my invention.

A further object of my invention is to provide a method of supplying alternating current to signaling and control apparatusv in a railway block system for dependable and efilcient control there- 20 of by relay switch devices.

Still another object of my invention is to provide a method of actuating control and signaling devices on a train, from wayside stations, by pneumatic pressure, whereby physical contact '25 with the moving train is avoided and dependable and efllcient operation of the system is assured, regardless of the speed of the train.

Still another object of my invention is to provide a method of actuating control and signaling 30 devices on a train, from wayside stations, by radiant energy, whereby physical contact with the moving train is avoided and dependable and eflicient operation of the system is assured, regardless of the speed of the train.

35 A still further object of my invention is to provide an arrangement for emergency control of trains in the block system of my invention in the event of failure of the power supply of the system.

40 Still another object of my invention is to provide a constant indication in both block and cab signals of a clear track when such condition prevails, in combination with means for restricting the use of compressed air to a minimum.

45 A still further object of my invention is to provide means for signaling at the wayside at the front end of any block, the entrance of a train at the rear end of the block.

Still another object of my invention is to pro- !)0 vide service and emergency control of brakes on a train in accordance with track conditions, in the block system of my invention.

Other and further objects of my invention reside in the circuit arrangements and methods of 55 operation hereinafter more fully set forth, with vention, shown in different positions; Fig. 6 is a modified form of track circuit for use in the system of my invention for speed control in isolated 10 blocks; and Fig. 7 is a modified form of circuit actuating means employing light sources and photo-sensitive devices.

Railway block systems heretofore known have employed various devices for communication be- 15 tween a fast moving train and a wayside control and signal station; such devices being either of the direct contact type wherein electrical circuits are positively completed through a direct current source of supply, or the inductive type in which electrical circuits aboard the train are actuated by induced electromotive forces from track or wayside apparatus fed with alternating current of high frequency or distorted wave form. My invention employs alternating current from the standard power mains of the locality, applied to the rails in such a manner that increase of the voltage is not required by extended rail sections,

nor is the voltage commutated at any point by relay contacts in such a way as to produce sparking. Low voltages of low frequency may be employed with entire satisfaction. The system of my invention employs an arrangement for actu ating the signal and control circuits aboard the train by means of compressed air expelled at wayside points under the control of the block system, and adapted to actuate rocker arm switch members. In this manner, safety and dependability are assured, and apparatus essentially rugged inexpensive and simple, and easily main- 40 tained, is employed.

Referring to the drawings; Fig. 1 shows the arrangement of the wayside apparatus in schematic form. It will be understood that the track sections may be made of various lengths, and that connections to the track are made substantially as shown with respect to the separate block sections, while the apparatus may be housed at any convenient location, preferably adjacent the track and power lines to facilitate servicing, and the compressed air tank and valves are positioned in the block at a selected point or points for effective coaction with the apparatus carried by the train. In Fig. 1 it will be noted that the control system is a single line, and that no other interconnection or intercoupling is employed betzveen sections, except the common ground connection, which may be omitted when a common power supply system is employed.

On Fig. 1, I have designated blocks 1, 2, 3, and 4. Blocks 1 and 4 are merely indicated, but blocks 2 and 3 are shown essentially, the control from block 3 to block 2 to be fully set forth as an example of the operation of the system for control of a train running through block 2 towards block 3. Corresponding parts in the different blocks are designated by primed like reference characters in block 3.

Referring more particularly to block 3, voltage from power lines I is applied to a step-down transformer 2', and from the secondary thereof, at low voltage to the primary 3c-32) of a 1:1 ratio transformer 3' through a reactor coil 4'. The secondary 3a'3c' of thertransformer 3' has one terminal thereof connected with one terminal of the primary winding as at 3a, and the primary and secondary windings are arranged with the magnetic fields thereof in opposition, so that when the currents in the two coils are in the same phase, as when the other terminals, 3b and 3c, of the windings are connected together, the fields will neutralize each other. When the currents are of different phase, however, as when suitable impedance is inserted between the terminals 3b and 3c of the windings, a voltage appears across the impedance. Accordingly, in the system of my invention, the terminals 3c and 3b of the windings of transformer 3 are connected at the front end of a track section to respective rails 5' and 6, and to the rails at the rear end of the section is connected the actuating winding 1' of a relay switch device including a plurality of contact members and fixed contacts for'cooperation therewith. The impedance represented in the winding 1' has a voltage thereacross suflicient to actuate the contact members and to hold the same in raised position. A short circuit across terminals 31), 30', such as would be caused by a train in the block, would cause this voltage to disappear whereupon the relay contact members would be dropped. The fixed relay contacts control the operation of signal and control apparatus in the block ahead as well as in the same block, as will hereinafter be fully described. The current drawn from the secondary of transformer 2 with terminals 3b and 3c short-circuited, is somewhat greater than the normal current due to the decreased impedance in the device 3, as a whole, under such conditions; but the current in the rails is reduced to substantially zero by reason of the neutralization of the fields in the 1:1 ratio transformer which causes the-voltage across the rails to disappear.

Referring now to block 2, connected to'the power lines I is a 1:1 ratio transformer 8, connected like transformer 3, to provide a potential difference across impedance in series with the secondary winding. The impedance in this instance is found in the actuating coils of valve release mechanisms 9 and I0 connected with a compressed air tank l2. Electromagnetic means for short circuiting this impedance is provided in contact members 14 and fixed contacts 15, controlled by an actuating winding l6 which is adapted to efiect quick break but slow make of the contact members and contacts controlled thereby.

The actuating winding I5 is normally energized by power supplied from the lines I through two parallel switch elements, one controlled by relay winding 1, and the other by relay winding 1. So long as the track in block 3 is clear, the winding I6 is energized through contact member l1 and fixed contact l8. With contact .member l1 dropped against dead contact I8a', by the presence of a train in block 3, the operation of the winding I6 is controlled by the arm l9 and fixed contacts 20 and 20a, controlled by relay winding 1 which is fed from the power lines I through transformers 2 and 3 and tracks 5 and 6. The

'winding I6 is normally energized through contact 20 but upon entry of a train in block 2, contact member i9 is dropped. The momentary break in the circuit (contacts l1, l8 being considered open-by reason of'an advance train'in block 3) causes the winding l6 to'release contact member l4, thus opening the air valves 9 and ID by the operation of the actuating windings thereof through transformer 8. The power supply circuit to winding I6 is immediately completed again through contact 20a but due to a time delay in the winding I6 which constitutes it a slow acting relay device, the contact members 14 will not be raised for the duration of a predetermined period, during which the train passes the open valves and receives the pressure of the discharged air on suitable apparatus for controlling the operation of the train, as will hereinafter be described. With contact members l4 raised again, the valves 9 and II) are closed, although the train may still be within the block.

An additional air release valve 2| is provided on the tank H, with the actuating winding thereof connecteddirectly with the power lines I at all times. The valve 2| is constructed so that when energized, as normally, air is confined, but when deenergized by failure of the power supply, the valve 2! opens and air is discharged for controlling the operation of passing trains.

Referring. now to Fig. 2 which shows schematically the connection of the apparatus in the cab of the train. An alternating current power supply is indicated at 25, feeding the lines 26. A 1:1 ratio transformer v2| is connected, like transformer 3' in Fig. 1, to provide a potential difference across impedance in series with the secondary winding. The impedance in this instance is found in reactor coils 28 and 29, series connected. The voltage across reactor 28 is employed to energize the actuating winding 30 of a retarded relay device of the slow break, quick make type, including contact members 3| and 32 and fixed contacts coacting therewith. The voltage across reactor 29 is employed to energize the actuating winding 34 of a prompt acting relay device having a contact member 35 and coating fixed contacts. Means for short circuiting the reactors 28 and 29 is provided in contact members 36 and fixed contacts 31, controlled by an actuating winding 38 in a relay switch device which includes also contact members 39 and 40 and fixed contacts coacting therewith.

Relay winding 38 is energized from the power source 25 through a switch mechanism 4|, shown more particularly in Figs. 3, 4, and 5, adapted to be actuated by air pressure released through valves 9, l0 and 2| at wayside points and intercepted by the pivoted vane 42 on the switch mechanism II. In normal position, as shown, contact members 36, 39 and 40 are dropped, and reactors 28 and 29 supply a potential drop to windings 30 and 34, respectively. Brake control valves 45 and 46 are provided with release devices normally held closed by current from the source 25. The actuating winding in valve 45 is connected through contact members 34 and ii in raised position; and the actuating winding in valve 46 is connected through contact member 32 in raised position. Contact member 35 is adapted to be dropped immediately upon the operation of switch 4i by. an air blast from the wayside, and results in the application of service brakes by means of valve 45 "to check the train speed.

Immediately upon the actuation of switch 4|, a connection in shunt therewith is made through contact member 39 in raised position thereby prolonging the energization of relay winding 38. Means for breaking this shunt connection or holding circuit is provided in a push key 41 under the control of the engineer of the train. If the shunt is maintained for a sumcient time period, the retarded relay device under control of winding ill will be dropped, resulting in the application of emergency brakes by means of valve 46, to stop the train. The application of the emergency brakes may be forestalled by operation of push key 41, reenergizing windings 30 and 34, and the emergency brakes may be released by operation of a push button switch 48 to shunt the contact member 32 and its coacting contact, completing the circuit to the actuating winding in valve 46 for closing the valve. While the application of the emergency brakes may thus be relieved from automatic control, the same cannot be done with respect to the service brakes.

Referring to the switch device 4i as shown in Figs. 3, 4 and 5, a fixed contact a is provided in the form of a semi-circular band. A pivoted support 43 is provided for mounting the vane 42 parallel to the track. The support 4| also carries contact members 4!!) and He projecting within the semi-circular band 4la, out of contact therewith in the normal central position of the contact members maintained by virtue of coil spring elewinding 1, the contacts being closed with the contact member 52' raised under conditions of clear track in block 3. A load reactor 54 is provided in shunt with lamp 56. Under the same conditions of clear track in block 3, contact member 56' closes a circuit through contact 51' and the actuating winding of an air release valve 58 connected across the reactor 4 in the secondary circuit of power transformer 2. The voltage drop across the reactor 4 is dependent upon the current in the track circuit in block 2 and is small and insuflicient to operate the valve 58 when block 2 is clear; but with a train in the block, as shown at 60, creating a short circuit in the track, the current in reactor 4 is increased to a value sumcient to operate the valve 58 which directs a Jet 01' air in a selected horizontal plane in the path of a train in block 2. If block 3 is not clear, contact member 56' is dropped and the circuit to valve 58 is opened.

A contact 53a engageable by contact arm 52' when dropped, is connected in circuit with a reactor GI and a red lamp 62 across the power lines I. A load reactor 63 is provided in shunt with lamp 62. An air release valve 64 has an actuating winding connected in shunt with the reactor 6|. Thus, the red lamp will be lit and the valve 64 opened when the relay winding I is deenergized by the presence of a train in block 3, the valve 84 operating to discharge a let air in an individual selected horizontal plane in the path oi a train in block 2.

Similarly, a contact arm 61' coacts with a contact 61a in dropped position, to complete a v circuit from the power lines i through a reactor 69 and a yellow lamp 10, with the load reactor II in shunt with lamp. An air release I! has an actuating winding connected in shunt with the reactor 88. Thus, the yellow lamp will be lit and the valve I! opened by the presence 01 a train in block 3, the valve 12 also operating to discharge air in an individual selected horizontal plane in the path of a train.

It will be noted that green lights will be showing in the block system at all times when tracks are clear whereas in order to conserve energy, air is expelled for indicating a green signal in the cab 01'. a train only while the train is in any particular block. This has been described as effected by means of the increased current in reactor 4 when the track circuit 5, 6. is short circuited as at 80. By virtue of this feature, a further indication may be had in the nature of a signal at the front end 01' a block upon the entrance of a train at the rear. Thus a device such as a bell 13. or a blinker signal, connected in shunt with the reactor 4, like the actuating winding of valve 58, will serve to warn road crews which may be working on the track of the approach oi. a train. This system eliminates the use of special circuits for such signaling, as it is incorporated directly into the block system. A switch 14 may be employed to open the circuit in instances where this signal is unnecessary orundesirable at all times.

Considering Fig. 2 again, and the cab circuits for actuating the signal lamps, power from the source 25 is fed through separate 1:1 ratio transformers I and 18, connected like transformer 3' in Fig. l to provide potential drops across impedances in series with the secondary windings of the transformers l5 and 18 respectively. The impedances are found in relay windings I8 and 18, respectively, which control the operation of a plurality of contact members and fixed coacting contacts. A switch mechanism 80, adapted to be actuated by the air jet from valve I2, is connected in shunt with the impedance of winding I9; and a similar switch mechanism 8i, adapted to be actuated by air from valve 64, is connected in shunt with the impedance of winding 18. Another switch mechanism 82 is adapted to be actuated by air ejected from valve 58. The switch mechanisms 80, 8| and 82 are identical in form to the switch mechanism 4|, hereinbefore described, and, as indicated have a common connection, together with switch 4|, to the grounded side of the power source 26. As shown on Fig. 2, for indicating the cooperative relation of the switch mechanisms with the wayside air valves, valves 9, l0 and 2| discharge in the same horizontal plane for actuating switch mechanism 4i; whereas valves 58, 84 and 12 are arranged to discharge in separate horizontal planes for individually actuating switch mechanisms 82, ill and 80 respectively.

As shown in Fig. 2 in accordance with circuit conditions indicated in Fig. l, valve 58 is open and switch mechanism 82 is actuated. The function of switch 82, in conjunction with a relay device having a winding 83 controlled by switch 88, is to restore the green signal in the event other signals have been made. The circuits are shown in restored relation, with a green signal lamp 88 energized from the power source 28 through contact arms 88 and 81 and upper coacting contacts 88 and 88, respectively. Contact arm 85 and another 88 are controlled by relay winding 18; and contact arm 81 and another 81 are controlled by relay winding 19.

Upon actuation of switch 80, relay winding 18 will be deenergized and contact arm 81 will drop on contact 880, extinguishing green lamp and lighting a yellow lamp 8!. Contact arm 9| will also be dropped and will complete a circuit through contact Mo, to a relay winding 96, and through a contact arm 84 (dropped by relay winding 88, when deenergized), and a contact arm 85 in dropped position, so that relay winding 88 will be energized from the source 25. Contact arms 81 and 88 are raised by relay winding 96,

a "holding circuit being completed through contact arm 91 and a contact arm I88, in dropped position, in shunt with the switch mechanism 80, so that the yellow light will be maintained. The restoring action of switch 82 and relay winding 88 breaks the shunt or holding" circuit through contact arm 81 by deenergizing winding 96 by raising contact arm 84.

Upon the actuation of switch 8|, relay winding 18 will be deenergized and contact arm 85 will drop on contact 86a, extinguishing either green or yellow light and energizing a red lamp llll. At the same time, contact arm 88 will drop on contact 88a and a circuit will be completed through a relay winding I02 and contact arms 40 and 88 when dropped by relay windings 88 and 88 respectively. Contact arms I88, I03 and 88 will be raised by winding I82, deenergizing relay 8! at contact arm 85, whereupon contact arm 98 drops on contact 88a so that a holding circuit may be completed throughcontact arm 588, in shunt with switch mechanism 8! to maintain the red light at illl. Contact arm I80 when raised, and 81 when dropped, release the shunt on switch 88 so that relay winding 18 raises the contact arms 8'! and 8|, which conditions the green lamp circuit for operation upon the clearance 01' the red signal. This is effected as a result of the actuation of switch 4] which energizes relay winding 88, thereby raising contact arm 48. At the same time that the red signal is extinguished however, brakes are applied and the train speed checked. Prior to the automatic application of the brakes the engineer, will be advised of block conditions by the red signal. The red signal will also be extinguished by the re storing action of switch 82 and relay winding 88, the circuit to relay winding I02 being opened when contact arm 88 is raised. Relay winding Hi2, upon being deenergized at contact arm 98 or at contact arm 48, drops the contact arms I I8, I83 and 85, thereby releasing the shunt on switch 8i and permitting relay winding 18 once again to raise contact arms 85 and 89, restoring the green lamp circuit. Thus the red signal may be extinguished without the brakes having been automatically applied, and the train may resume speed,

Referring to the system as a whole, and considering clear trafllc in the block ahead, a train entering block 2, as at 80, will find conditions as shown in the drawings; that is, green lamp 88 will show lighted at the wayside, and valve 58 is opened by the entrance of the train in the block, as described, so that the clear track signal may be shown in the cab by actuation of the restoring circuits through relay 83, and the lighting of lamp 84, if it be not already lighted. Valve 58 closes when the train leaves the block.

Considering now that the train has passed into block 3, creating a condition for block 2 of an occupied block ahead. Green lamp 50 in block 2 is extinguished, red and yellow lamps 82 and ID are lighted and the corresponding valves 84 and 12 are-opened, and the circuit to relay I8 is opened through contacts ll, I8, all by the action of relay switch I. A train entering at the rear of block 2, as at 68, now will find caution and danger signals. The yellow lamp 18, and valve 12 may be positioned near the entrance of the block, so that the engineer will be advised by wayside and cab signals to proceed with caution. And the red lamp 62 and valve 84 may be positioned a predetermined dis tance from the exit of the block so that the engineer will be advised by wayside and cab signals to stop. Furthermore, the brake control valves 9 and I are opened under these conditions and may be positioned adjacent or beyond the stop signal 62 and valve 84 so that the brakes will automatically be applied and the train stopped within the block. The emergency application of brakes is an added safety measure and will occur in instances where the engineer is not able to operate the controls. Normally, the emergency operation is forestalled by the use of switch 48 and the train is stopped under the control of the engineer who may operate switch 81 to release the brakes and proceed when the block ahead is clear, as shown by the lighting of the wayside green lamp 511, which may be positioned at the entrance to the next block, block 3, within which it is controlled. Yellow and red lamps are extinguished with the lighting of the green lamp 50, and in the cab, the green lamp is lighted again by the opening of contacts 48 by relay 38 which releases relay I02.

The restoring action of switch 82 and relay 83 is taken advantage of by positioning valve 58 at the wayside to be met by the train prior to valves 9 and Ill, so that if the block ahead is clear before the train reaches valves 8 and ill, the green lamp 84 in the cab will be lighted and .the engineer may resume speed immediately, and by holding switch 41 open the operation of valves 8 and ill will not take effect. Duplicates of any of the valves, particularly of valve 58, may be employed along the wayside, especially in very long blocks, so that clearance of the block ahead may be promptly noticed in the cab.

The speed control system of my invention may be applied to isolated blocks for controlling the speed of trains on bad roadbeds, bridges, curves, or grades, in the manner shown in Fig. 6. The power connections to the track include transformers 2 and 8" and the power take of! feeds a, relay winding 1 with an associated contact arm l9" and contacts 20" and 20a". A connection from l9" alone feeds a'relay winding of the slow acting type at l6" for controlling the operation of valves 9" and I0" fed from a transformer 8", all in a manner similar to that described in connection with Fig. 1, with the exception of the control connection to winding II" from the track ahead. Thus, any train entering a block so prepared would be controlled in accordance with predetermined standards and regardless of traflic conditions ahead.

till

tilt

Compressed air tanks it, fill, it", may be maintained with a pressure of 100 pounds per square inch, for example, by an electric driven compressor controlled by the tank pressure in a well known manner. Vent openings of one inch diameter are satisfactory, with a clearance of approximately one-half inch from the enacting.

pivoted vane which may be recessed in the side of the train, 1

The lamps employed, particularly in the way side track system at to, $2, and it, are of the series type and operate by the potential drop across the respective reactors 5 3, st, ll, in shunt therewith. lhese lamps have rugged filaments and operate on low voltage, and are entirely dependable.

In lieu of compressed air tanks and cooperating valves and vane switch mechanisms as described, ll may employ radiant energy and radiant energy it "pensive devices such as photoeelectric cells. l traclr system the air release valves may be :3 by light sources adapted to project light tn-.5 track, wliile in the can system, photo sitive devices replace the vaneswitch mesh-- it, til, ill and t2, and are adapted to duct current when light rays are intercepted on the photo-sensitive elements. Fig. 1 indicates this modification of the system of my invention and shows lamps ltd, W5, it'd, ill? and Edit to be controlled by track conditions as hereinbefore described with regard to valves lit, t ll, it, ll and ill, respectively. Lamp tilt, Fig. 1', may be ener glued from a separate power source lit held connected by the relay device i it normally enersized from the power lines l, the function oi lamp ltd being similar to that of valve El, both devices being actuated upon the failure of the power supply for lines 9. In the cab system, photo-sensitive devices lid, H5, lit and lit connected with a source of direct current poten that] lit through relay devices tit, tilt, till, 522, respectively. Light falling on any oi the pliotosensitive devices will cause'enereiaation or the respective relay to close contacts connected in the control and signal circuits as shown in 2. will be understood that the lamps and photo sensitive devices are correspondingly disposed in difierent horizontal planes similar to the ar rangeznent of air valves and vanes shown in Figs. 1 and 2. Infra-red or like invisible may be employed in the arrangement shown in Fig. l in order to increase the selectivity and dependability of the system.

While X have thus described my invention in certain preferred embodiments, I desire it understood that no limitations upon my invention are intended, and that modifications may be made such as are within the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. in a railway bloclr system including the rails of a track: section for passage oi a train there over, a source of alternating current; a 1:1 ratio transformer having first and second windings arranged in opposition, said first winding con nected directly across said source and at one end to a track rail, said second winding connected to the other end of said first winding and to the other traclr rail, and an impedance device con" nected across the track rails and consequently in series with said second winding; whereby normally the track rails are energized by a voltage resulting from phase shift in the magnetic field of said transformer due to said series connected impedance device and with the rails shunted by a train the output from the transformer to the rails is substantially zero.

2. In a railway block system, the arrangement set forth in claim 1 wherein said impedance device comprlses the inductive actuating winding of a relay switch device having control means operable thereby for selectively transmitting control energy to a train in said track section, said relay switch device being actuated by the presence of a train in said track section which substantially shunts the inductive actuating Winding of said device.

3. In a railway block system, means for controlling a train entering succeeding sections in a. series of track sections, comprising means for supplying electric control energy to the track in each section, relay switch. means connected with each track section and normally energized therefrom, said relay switch means including a plurality of cooperative contact elements; a relay device and control means adapted to be actuated thereby in each track section; and means includtiny cooperative contact elements controlled bythe relay switch means in a succeeding section for conditioning relay device in the adjacent preceding section for actuation by the relay switch means in the said preceding section, and means including cooperative contacts controlled by the relay switch means in the said. preceding section for actuating the relay device in the same section.

i. In a railway 'nloclr system, means for con trolling a train in a series of track sections as set forth in claim and wherein said relay device is of the qlllCiii-blfidk, slow -maize type actuated by relay switch contact elements so connected and arranged as to restore the circuit through sail. relay device immediately upon the actuation thereof.

ii. In a train control system, means for autoniatically actuating train carried control apparates comprising a source of alternating current, a 1:1 ratio transformer having first and second windings, said flrst winding connected directly said source, a reactor connected with one end of each of said flrst and second windings, the other ends of said windings being connected together, said reactor being in series with said secand winding across said source, whereby normally said reactor is energized by a voltage resulting from phase shift in the magnetic field of said transformer due to said series connected reactor; relay switch means including a. plurality of contact elements certain of which are connected in shunt with said reactor, a relay device energized by the potential drop normally across said -reactor and adapted to actuate said train control apparatus, and-means operable in accordance with trafilc conditions in the system for energizing said relay switch means for actuating said relay device, the output from said transformer to the reactor being substantially zero with said shunt contact elements closed by the operation of said relay switch means.

6., in a train control system, means for autornatically actuating train control apparatus, which comprises a source of alternating current, relay switch means including a plurality of contact elements, a pair of relay devices energized from said source and adapted to be controlled by break, quick-make type, a vane type switch operable to energize said relay switch means for actuating said relay devices, and actuating means for said vane type switch comprising wayside pneumatic devices operable in accordance with trafilc conditions in the system.

7. In a railway block signal system, means for signaling a train entering succeeding sections in a series of track sections comprising means for supplying electric control energy to the track in each section, relay switch means connected with each track section and normally energized therefrom, said relay switch means including a plurality of cooperative contact elements; signal lamps associated with each track section, means including normally closed contact elements controlled by the relay switch means in a succeeding section for energizing one of said lamps in an adjacent preceding section, means including normally open contact elements controlled by the relay switch means in said succeeding section for energizing others of said lamps in said preceding section, said relay switch means being actuated by the presence of a train in the associated succeeding track section.

8. In a railway block signal system, means for signaling a train in a series of track sections as set forth in claim6 and including control devices electrically connected with the last mentioned lamps and actuated in conjunction therewith for transmitting the signal indication to a train in the associated section, and a control device arranged for operation in accordance with the condition of the first mentioned lamp, and means for actuating the last said control device by a train in the associated section for transmitting a signal indication to said train.

9. In a relay block system, the arrangement set forth in claim 1 and including signal means connected in series with the said first winding of said transformer across the source of alternating current; said means being inoperative under current conditions in the said first winding with said rails energized from said transformer, and operative under increased current conditions in said first winding with the rails shunted by a train for signaling ahead in said section the presence of a train in said section.

,10. In a train signal system, meansfor automatically actuating signal devices on a train, which comprise a source of alternating current, relaydevices energized from said source and cooperative for controlling said signal devices, a plurality of relay switch means, and a plurality of vane type switch devices actuated by wayside pneumatic means operable in accordance with traflic conditions in the system for controlling the operation of said relay devices, said relay switch means being operative upon the actuation of said vane type switch devices to maintain the effect of said switch devices.

11. In a train signal system, means for automatically actuating signal devices on a train, which comprise a source of alternating current, relay devices energized from said source and cooperative for controlling said signal devices, a plurality of relay switch means, and a plurality of vane type switch devices actuated by wayside pneumatic means operable in accordance with traffic conditions in the system for controlling sulated from each other, means for supplying energy to the track in each block, a relay device for each block energized through the track in the respective block, contact means controlled by the individual relay devices and operative to actuate signal and control devices in respectively adjacent blocks, said signal and control devices including pneumatic pressure release valves on the way-. side in the respective block, and pressure responsive devices on a train operable in said block.

13. In a railway train control system, actuating means on the wayside comprising a compressed air storage tank and a plurality of air release valves connected therewith each having an electrically operated actuating device, said air valves being disposed in different selected horizontal planes and operative to project air jets normal to the tracks; and a plurality of switch mechanisms carried by a moving train in corresponding selected horizontal planes and in positions to be actuated by the respective air jets from the wayside actuating means, the operation of said air release valves being selectively controlled in accordance with the trafilc conditions in said system.

JOHN C. MCDONALD.

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