US2061753A - Railway braking apparatus - Google Patents

Description

H. L. BONE 2,061,753

2 Sheets-Sheet l 70 source I [I u id Uressul'c INVENTOR Herbert. LBzme low releas in BY QZQZZQ a In atmospher Hi4 ATTORNEY Nov. 24, 1936.

RAILWAY BRAKING APPARATUS Filed June 5, 1935 Nov. 24, 1936. H. BONE RAILWAY BRAKING APPARATUS 2 Sheets-Sheet 2 Filed June 5, 1955 Slaw releasiny lawpicicup and slow r626 ase.

ea-5o P4545 P 70-90 I R O T N E m To afmos To source 13/ [add O7 i 2 Herbert L. Bone I a 611W H18 ATTORNEY Patented Nov. 24, 1936 UNITED STATES PATET QFFIQE RAILWAY BRAKING APPARATUS Application June 5, 1935, Serial No. 25,118

23 Claims.

My invention relates to railway braking apparatus, and has for an object the provision of improved means for automatically controlling the braking action of a car retarder in accordance with the speed of a car passing therethrough.

I will describe two forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a view, partly sectioned and partly diagrammatic, illustrating one form of apparatus embodying my invention. Fig. 2 is a view similar to Fig. 1 illustrating another form of apparatus embodying my invention.

Similar reference characters refer to similar parts in both views.

Referring first to Fig. 1, the reference characters I and I designate the track rails of a stretch of railway track over which cars normally move in the direction indicated by the arrow under such conditions that it is desirable to at times control the speed of the cars automatically. For example, the stretch of track here shown might be in a classification yard of the hump type through which cars move under the influence of gravity. It is obvious that in service of this kind, the speed of individual cars or strings of cars will vary through wide limits, depending among other things, upon the speed at which they go over the hump, the temperature, the weight of the car and its contents, and the condition of the car as to whether it is a free running car or otherwise.

In order to control the speed of the cars, the stretch of track illustrated in the drawings is provided with a car retarder R. which, in the form here shown, comprises two braking bars 2 and 3 extending parallel with, and located on opposite sides of, rail I, and two similar braking bars 2 and 3 extending parallel with, and located on opposite sides of, rail l The braking bars 2, 3, 2 and 3 are operated by a fluid pressure motor M comprising a cylinder 4 containing a reciprocable piston 5 attached to one end of a piston rod 6. The braking bars 2, 3, 2 and 3 are operatively connected with the piston rod 6 through a suitable linkwork including a bell crank I and a lever B pivotally supported at point 9. When piston 5 occupies its extreme right-hand position, in which it is illustrated in the drawings, the braking bars occupy their non-braking or ineffective positions in which they are out of engagement with the wheels of a car traversing the rails I and I When piston 5 is moved to its left-hand position, however, as when fluid pressure is admitted to the right-hand end. of cylinder 4, the braking bars 2, 3, 2 and 3 are moved toward the associated rail to their efiective or braking positions in which they will engage the wheels .of a car traversing the rails I and I to retard the speed of the car.

The braking bars 2, 3, 2 and 3 are constantly biased to their non-braking positions by any suitable means here shown as a spring 20 which is interposed in the cylinder 4 between the lefthand end of the cylinder and the piston 5.

The motor M is controlled by two magnet valves V and V each comprising a valve stem I I] biased to an upper position by means of a spring II, and provided with a winding. I2 and an armature I3. When valve V is energized as shown in the drawings, valve stem III of this valve is moved downwardly against the bias of spring II, and a pipe I 4 which communicates with the right-hand end of cylinder 4 of motor M is then connected with atmosphere through a port I5. When valve V is deenergized, however, pipe I4 is disconnected from atmosphere and is connected with a pipe It leading to valve V When valve V is energized, valve stem Iil of this valve moves downwardly, and connects pipe I6 with a pipe H which is constantly supplied with fluid pressure, usually air, from a suitable source not shown in the drawings, but when valve V is deenergized, as shown in the drawings, pipe I6 is then disconnected from pipe I1. It will be apparent, therefore, that when valve V is energized, the region of the cylinder 4 of motor MI between the piston 5 and the right-hand end of the cylinder is connected with atmosphere, so that the braking bars of the car retarder will then be held in their ineffective or non-braking positions by the spring 29. When, however, valve V is deenergized and valve V is energized, fluid pressure will be supplied to the right-hand end of cylinder 4 of motor M, thus causing the braking bars to move to their 4 effective or braking positions. It will be obvious that when the braking bars are moved to their braking positions, they will exert a braking force which is proportioned to the pressure of the fluid which is then supplied to the right-hand end of motor M.

The valves V are controlled in part by a plurality of pressure responsive devices P P and P' each comprising a Bourdon tube 2| connected to a pipe I 4 which communicates with 55 the pipe I4, so that these Bourdon tubes are constantly subjected to the pressure of the fluid in the right-hand end of cylinder 4 of motor M. Each Bourdon tube controls two contacts 22-22 and 2222 The pressure responsive devices P P4545 and P are so constructed and so adjusted that they will operate successively as the pressure in the region of cylinder 4 between the piston 5 and the right-hand end of the cylinder increases. For example, for all pressures below 20 pounds per square inch, the contacts 2222 of each of these devices is closed. If the pressure exceeds 20 pounds per square inch, however, contact 2222 of device P opens, and if the pressure exceeds 30 pounds per square inch, contact 22-42 of device P closes. In similar manner, the pressure responsive devices P and P are adjusted to open their contacts 22--22 at 45 and 70 pounds per square inch, respectively, and to close their contacts 22-22 at 55 and 80 pounds per square inch, respectively. Of course, these specific pressures are not essential but are only mentioned for purposes of explanation.

The valves V are also controlled in part by means of two slow releasing relays A and B which relays, in turn, are controlled by speed responsive apparatus in a manner which will be described in detail hereinafter.

The valves V are further controlled by means of a manually operable lever L which, as here shown, is capable of assuming five positions, indicated by dotted lines in the drawings, and designated by the reference characters p to p inclusive. Operatively connected with the lever L is a contact arm 23 which selectively engages a plurality of fixed contacts 23 23 23 23 and 23 to close a contact 23-23 2323 23--23 2323 or 2323 according as lever L occupies its 12 its p its its p or its 79 position.

The lever L will usually be located at a point remote from the braking apparatus, as in the control cabin of a classification yard car retarder system, and will be connected with the braking apparatus by means of line wires extending from the control cabin to the braking apparatus.

As shown in the drawings, the relays A and B are both deenergized and the lever L occupies its 19 or ofi position. Under these conditions all circuits for valve V are interrupted, and a circuit for valve V is closed, which latter circuit passes from a suitable source of current here shown as a battery C through wire 24, back contact 25-45 of relay A, wire 26, contact 23-23 of lever L, line wire 21, wires 28, 29, 30 and 3|, winding H. of valve V and wire 32 back to battery C. Valve V is therefore deenergized and valve V is energized. Since valve V is deenergized, pipe i! is disconnected from pipe 16 and the supply of fluid pressure to cylinder 4 is therefore cut off, and since valve V is energized, cylinder 4 is connected with atmosphere. The braking bars are therefore held in their ineffective or non-braking positions by the spring 20. The contact ?2-22 of each of the pressure responsive devices P is closed, and the contact 22-22 of each of these devices is open.

I will now assume that with the relays A and B both deenergized the operator moves lever L to its p position. Under these conditions, the circuit which was previously closed for valve V will become interrupted at contact 23-23 of lever L and a circuit for valve V will become closed at contact 2323 of lever L, which latter circuit may be traced from battery C through wire 24, back contact 2525 of relay A, wire 26, contact 23-23 of lever L, wires 33, 34 and 35, contact 2222 of pressure responsive device P2040, wires'36, 3'! and 38, winding I2 of valve V and wire 32 back to battery C. Valve V therefore becomes deenergized and valve V becomes energized. The deenergization of valve V disconnects pipe [4 from port 15, and connects pipe 4 with pipe l6, while the energization of valve V connects pipe I! with pipe 16. As a result, fluid at full line pressure is now supplied to the right-hand end of cylinder 4 of motor M, thus causing the braking bars to move to their effective or braking positions. As soon as the pressure of the fluid in the right-hand end of cylinder 4 of motor M reaches pounds per square inch, contact 22-22 of pressure responsive device P- will open and will interrupt the circuit just traced for valve V Valve V will then become deenergized and will cut oiT the supply of fluid to the right-hand end of cylinder 4 until the pressure in the motor again decreases below 20 pounds per square inch, at which time valve V will again become energized, and will again admit fluid to the right-hand end of cylinder 4. If the fluid in the right-hand end of cylinder 4 of motor M now increases to a pressure of 36 pounds per square inch for any reason, contact 22-42 of pressure responsive device P will become closed and will complete a circuit for valve V which circuit passes from battery C through wire 24, back contact ?525 of relay A, wire 26, contact 2323 of lever L, wires 33, 34 and 35, contact 2222 of pressure responsive device P wires 29, 39 and 3|, winding I2 of valve V and wire 32 back to battery C. Valve V will therefore become energized and will vent fluid from cylinder 4 until the pressure again decreases to 30 pounds per square inch, at which time contact 22-22 will open and deenergize valve V It will be seen, therefore, that when relays A and B are both deenergized and lever L occupies its 72 position, the braking bars will be held in their braking positions by a pressure of between 20 and 30 pounds per square inch.

I will now assume that lever L occupies its p position and that relay A becomes energized. Under these conditions all circuits which were previously closed for the valves V and V will 4 be interrupted, and a circuit for valve V will become completed which passes from battery C through wire 24, front contact -25 of relay A, wires 39, 28, 29, and 3|, winding ll of valve V and wire 32 to battery C. Valve V will therefore become energized and will vent fluid from the right-hand end of motor M, thus permitting the biasing means to return the braking bars to their non-braking positions in which they are shown in the drawings.

If relay B becomes energized when lever L occupies its 10 position, all parts will remain in the positions which they previously occupied since none of the circuits for the valves V are controlled by this relay in this position of lever L.

I will now assume that the relays A and B are both deenergized and that the operator moves the lever L to its p position. Under these conditions, valve V if it is not already deenergized, will become deenergized, and valve V will become energized over a circuit which passes from battery C through wire 24, back contact 25 -25 of relay A, wire 26, contact 23-23 of lever L, wire 40, back contact H-4l of relay B, wire 42, contact 22-42 of pressure responsive device P wires Cil 31 and 3B, winding l2 of valve V and wire 32 back to'battery'O Fluid pressure will therefore now be admitted to the right-hand end of cylinder 4 of motor M until the pressure of the fluid in the cylinder increases to pounds per square inch, at which time contact 22--22 of pressure responsive device P will open and will deenergize valve V If the pressure in the righthand end of cylinder 4 now increases to 55 pounds per square inch, contact ZZZ-22 of pressure responsive device P will become closed and will complete another circuit for valve V this latter circuit passing from battery C through wire 24, back contact 2525 of relay A, wire 26, contact 23--23 of lever L, Wire 40, back contact ll ll= of relay B, wire 62, contact 2222 of pressure responsive device P wires 30 and 3 I, winding [2 of valve V and wire 32 to battery C. Valve V will therefore become energized and will exhaust fluid from the right-hand end of cylinder 4 until the pressure decreases to that at which contact 2222 of pressure responsive device P opens. It will be apparent, therefore, that when lever L occupies its p position, the braking bars will be held in their braking positions by a pressure of between 45 and 55 pounds per square inch.

If when lever L occupies its p position relay A becomes energized, all circuits which were previously closed for the valves V and V will become interrupted and the previously described circuit for valve V including front contact 25-25 of-relay A will become closed, thus causing the braking bars to move to their non-braking positions in the'manner previously described.

If when lever L occupies its p position, relay' B becomes energized, all circuits which were previously closed for the valves V and V will become interrupted, and a circuit for valve V will become closed, which circuit is similar to the circuit which becomes closed for this valve when relays A and B are both deenergized and lever L occupies its p position, with the exception that this latter circuit includes, instead of contact 23-23 of lever L and wire 33, contact 23-23 of lever L, wire 40 and'front contact M- ll of relay 1B. When this circuit becomes closed, fluid will be vented from the right-hand end of cylinder 4 of motor M until the pressure in this end of the cylinder decreases to 30 pounds per square inch at which time the resultant opening of contact 22-42 of pressure responsive device P will interrupt the circuit which was previously closed for valve V at this contact, thus deenergizing this valve, and hence preventing further exhaust of fluid to atmosphere. If while relay Bis energized the pressure in the righthand end of motor M decreases to that at which contact 22-22 of pressure responsive device P becomes closed, valve V will then become energized overa circuit which is similar to that over'which this valve becomes energized when the relays A and B are both deenergized and lever L occupies its 12 position, with the exception that this latter circuit includes contact 2323 of leverL, wire il, and front contact 4 I-4 I' of lever Linstead of contact 23-23 of lever L, and wire 33. It will be seen, therefore, that if relay B becomes energized when lever L occupies its p position, the pressure in the right-hand end of cylinder (l of motor M will decrease to that corresponding to the 11 position of lever L, and will be subsequently maintained at this pressure as long as relay B remains energized and lever L remains in its 10 position.

I will'now assume that the relays A and B are both deenergized and that the operator moves lever L to its 10 position. Under these conditions, valve V will become energized over a circuit which passes from battery C through wire 24, back contact 25-45 of relay A, wire 26, contact 23-43 of lever L, wire 43, back contact 4444 of relay B, wire 45, contact 2222 of pressure responsive device P wire 38, winding 12 of valve V and wire 32 to battery 0. Fluid will therefore nowbe supplied to the right-hand end of cylinder 4 until the pressure in this end of the cylinder reaches '70 pounds per square inch, which is the pressure at which contact 22-22 of pressure responsive device P" opens. If the pressure in the right-hand end of cylinder 4 now increases to 80 pounds per square inch, contact 22--22 of pressure responsive device P' will become closed and will complete still another circuit for valve V may be traced from battery C through wire 24, back contact 25-45 of relay A, wire 26, contact 23-23 of lever L, Wire 43, back contact A L-M of relay B, wire 45, contact 2222 of pressure responsive device 1 wire 31!, winding l2 of valve V and wire 32 back to battery C. Valve V will therefore become energized until the pressure in the righthand end of cylinder 4 decreases to 80 pounds per square inch. It will be seen, therefore, that when relays A and B are both deenergized and lever L occupies its p position, the right hand end of cylinder 4 of motor M will be supplied with fluid at a pressure of between and pounds per square inch, so that the braking bars will exert a corresponding braking force.

If with lever L in its 10 position relay A becomes energized, both circuits which were previously closed for valves V and V in this position of the lever will become interrupted and valve V will become energized over the previously describe-d circuit for this valve including front contact 252 5 of relay A. It follows, therefore, that under these conditions the braking bars will again be moved to their non-braking positions by the biasing means 20.

If when lever L occupies its p position relay B becomes energized, the opening of back contact l4 l4 of relay B will interrupt the circuits which were previously closed for either valve V or V while the closing of the front contact id-M of this relay will complete another circuit for valve V or another circuit for valve V according as contact 22-22 or contact 2222 of pressure responsive device P is then closed. These latter circuits for the valves V and V are similar to those which are closed for these valves when lever L occupies its p position, with the exception that these circuits each includes contact 23-23 of lever L, wire 43, front contact i l-M of lever L and wire ll in place of contact 2323 of lever L and wires 33 and M. It will be seen, therefore, that if relay B becomes energized when lever L occupies its p position, the pressure in the righthand end of cylinder 4' of motor M will be reduced to the same pressure which is maintained in this motor when lever L occupies its 11 position.

I will now assume that relays A and B are both deenergized and'that lever L is moved to its 10 position. Under these conditions valve V will become energized and will subsequently remain energized over a circuit which passes from battery C through wire 24, back contact 2li2li of relay A, wire 26, contact 23-23 of lever L, wire 48, back contact 4949 of relay A, wires 53,36,31 and 38, winding l2 of valve V and wire 32 back to battery 0. It will be apparent, therefore, that This latter circuit for valve V under these conditions, the braking bars will be held in their braking positions by fluid at full line pressure.

If, when lever L occupies its p position, relay A becomes energized, the braking bars will again be moved to their non-braking positions in the manner previously described. If, however, under these conditions, relay B becomes energized, the opening of back contact 49-49 of relay B will interrupt the circuit which was then closed for valve V or V as the case may be, and will close another circuit for valve V This circuit is similar to that which was closed for this valve in the 12 position of the lever when the pressure in the right-hand end of the cylinder was greater than 80 pounds per square inch, with the exception that this circuit includes contact 23-23 of lever L, wire 48, and front contact 49-49 of relay B instead of contact 2323 of lever L, wire 43, and back contact i l-44 of relay A. Valve V will therefore become energized and will vent fluid from the right-hand end of cylinder 4 of motor M until the pressure in this end of the cylinder decreases to 80 pounds per square inch at which time the resultant opening of contact 2222 of pressure responsive device P will deenergize valve V If the pressure in the right-hand end of cylinder 4 of motor M further decreases to 70 pounds per square inch under the conditions just described so that contact 22--2':! of pressure responsive device P becomes closed, valve V will become energized and will admit fluid to the right-hand end of cylinder 4 of motor M by virtue of a circuit which is similar to that which is closed for this valve under corresponding conditions when lever L occupies its p position with the exception that this circuit includes contact 2323 of lever L, wire 48, and front contact 4969 of relay B instead of contact 23-23 of lever L, wire 43, and back contact 444 l of relay B.

It should be observed that if, when relays A and B are both deenergized, the operator moves lever L from a position corresponding to a higher braking force to a position corresponding to a lower braking force, the apparatus will immediately and automatically reduce the braking pressure to a value corresponding to the new position of the lever in a manner which will be apparent from the drawings without tracing the sequence of operation in detail.

When relays A and B are both deenergized and lever L occupies any one of its 11 12 p or p po-' sitions, so that the braking bars occupy their braking positions, and the operator wishes to restore the braking bars to their non-braking positions in which they are illustrated in the drawings, he will restore lever L to its p or off position. When he does this, all circuits previously traced for valve V will be interrupted, and the circuit previously described for valve V including contact 23-23 of lever L will become closed. Valve V will therefore become deenergized and valve V will become energized. As a result, the supply of fluid pressure to the right-hand end of cylinder 4 of motor M will be cut oil and the fiuid which was previously supplied to this end of the cylinder will be vented to atmosphere. The braking bars will therefore move, due to the bias of spring 20, to their ineffective or non-braking positions. When the braking bars reach their nonbraking positions, all parts will be restored to the positions in which they are shown in the drawings.

The previously mentioned speed responsive apparatus for controlling the relays A and B comprises a series of relatively short insulated control sections 5l 5| etc. which are formed in the rail I. These control sections will usually be of uniform length and their lengths may be varied as conditions require, but the lengths of these sections will preferably be such that two wheels of a car can not occupy the same section at any one time.

The speed responsive means for controlling relays A and B also includes a speed control lever S which, as here shown, is capable of assuming three positions, designated s s and s respectively, in the drawings, and which is provided with three contacts 52, 53 and 54. Contacts 52 and 53 are so arranged that these contacts will be closed when and only when the lever occupies its s position, and contact 54 is so arranged that this contact will be closed in any position of the lever except its s or off position.

Associated with each control section 5| is a track relay designated by the reference character D with a suitable distinguishing exponent, two resistors each designated by the reference character R with a distinguishing exponent and subscript, and two timing relays each designated by the reference character T with a suitable distinguishing exponent and subscript.

The track relays D D D, etc. are similar relays, and as here shown, each of these relays is connected in a track circuit which includes, in addition to the associated control section 5|, the rail i= contact 54 of speed control lever S, and a suitable source of current here shown as a battery F. It will be apparent, therefore, that when contact 54 of lever S is open, or when this contact is closed and all of the sections 5| are unoccupied, all of the track relays D will be deenergized, but that, when contact 54 is closed, and a car wheel moves onto any one of the sections 5| the associated track relay D will become energized. It will also be apparent that the duration of the time interval during which a track relay remains energized when it has once become energized will depend upon the time required for a car to traverse a distance which is equal to the length of the associated control section, and hence upon the speed of the car.

The timing relays T1 T1 T1, etc. are also similar relays, and as here shown, each of these relays has a release time which is equal to that required for a car to traverse a distance equal to the length of one of the control sections 5| when the car is traveling at the maximum control speed at which it is desired to have the car leave the retarder. tion I will assume that each relay T1 is adjusted to have a release time which is equal to that required for a car traveling at 7 miles per hour to traverse the distance equal to the length of one of the control sections 5|. Each relay T1 is provided with a pickup circuit which includes the winding of the relay, back contact 55-55 of the associated track relay D, a wire 63, a battery E, and a wire 62.

The timing relays T2 T2", T2, etc. are likewise similar relays, and each of these relays is constructed to have a release time which is equal to the time required for a car to traverse one of the sections 5| when the car is traveling at a speed which is slightly higher than the maximum control speed. For example, assuming that the maximum control speed is '7 miles per hour, each timing relay T may be adjusted to have a release time which is equal to that required for a car traveling For example, for purposes of illustraat 8 miles per hour to traverse a distance equal 7 to the length of one of the control sections 5|. Each timing relay T2 is provided with a pickup circuit which includes the winding of the relay, a back contact 5858 of the associated track relay D, a wire 59, a battery J, and a wire 60.

With the timing relays controlled in the manner thus far described it will be apparent that when none of the track relays D are energized, as is the case when contact 54 of lever S is open, or when this contact is closed and no car is traversing the stretch of track shown in the drawings, all of the timing relays T will be energized, but that, when contact 54 is closed and a car is traversing the stretch of track shown in the drawings, each time a car wheel moves onto one of the control sections 5! and causes the associated track relay D to become energized, the timing relays controlled by such track relay will become deenergizedand will remain deenergized for a time interval which depends upon the speed of the car. It followsthat if the speed of the car is less than 8 miles per hour but greater than 7 miles per hour, the associated timing relay T2 will release its armature and close its back contact 65 and that, if this car speed is less than 7 miles per hour, both the associated timing relay T2 and the associated timing relay T1 will release their armatures and will close their back contacts 65 and 56, but that, if the speed of the car is above 8 miles per hour, neither of the associated timing relays will release its armature.

For reasons which will be made clear as the description proceeds, it is desirable to be able to at times vary the release times of the timing relays T to cause them to close their back contacts at different car speeds, and for this purpose each of the timing relays T1 is provided with a shunt circuit which includes the associated resistor R1, while each of the timing relays T2 is provided with a similar control circuit which includes the associated resistor R2. Referring particularly to the timing relays T18 and Tz the shunt circuit for the relay T1 includes front contact 55 of track relay D resistor R19, wire 64, contact 53 of lever L, and wire 62, while the shunt circuit for the timing relay T2 includes front contact 58-43 of relay D resistor R2 Wire 6|, contact 52 of lever S, and wire 60. The shunt circuits for each of the other timing relays are similar to those just described for the timing relays T15 and Tr.

It will be readily understood that if more than two release times are desired for each timing relay, these relays may be provided with additional shunt circuits, each similar to the shunt circuits shown but each having a diiferent resistance and so arranged that different ones of these circuits may be rendered effective by moving lever S to different positions. It will also be readily understood that the release times of the timing relays T when the shunt circuits shown are cut in may be regulated to any desired value within the limits of design of these relays by choosing the proper Value of the resistance for the associated resistor R. As here shown, the resistances of the resistors R2 are such that when these resistances are cut in, the relays T2 will release at all car speeds below 5 miles per hour, and the resistances of the resistors R1 are such that when these resistors are cut in, the associated relays T will release at all car speeds below 4 miles per hour.

The slow releasing relays T2 control relay B by virtue of a plurality of parallel pickup circuits, each of which includes a suitable source of current here shown as a battery G, and the front contact 65 of a different one of the timing relays T2. It will be seen, therefore, that when all of the timing relays T2 are energized, relay B will be deenergized, but that when any one of the timing relays T2 becomes deenergized and remains deenergized for a sufficient interval of time to cause it to close its back contact 65, relay B will become energized.

Relay B is made sufiiciently slow releasing so that, when a car is traversing the stretch of track shown in the drawings at a speed which is just slow enough to cause the timing relays T2 to successively close their back contacts 65, this relay will bridge the interval of time which will elapse under these conditions between the opening of the back contact 55 of one timing relay T2 due to a wheel of the car having departed from the associated section 5|, and the closing of the back contact 65 of the timing relay T2 next in advance due to the same wheel of the car having moved onto the section 5| associated with this latter timing relay.

The slow releasing relays T1 control relay A by virtue of a plurality of pickup circuits each of which includes a suitable source of current, here shown as a battery H and the back contact 66 of a different one of the timing relays T1. It will be seen, therefore, that when all of the timing relays T1 are energized, relay A will be deenergized, but that when any one of the timing relays T1 becomes deenergized and remains deenergized for a sufficient interval of time to cause it to close its back contact 65, relay A will become energized.

Relay A is made sufficiently slow releasing so that, when a car is traversing the stretch of track shown in the drawings at a speed which is just slow enough to cause the timing relays T1 to successively close their back contacts 55, this relay will bridge the interval of time which will elapse under these conditions between the opening of the back contact 66 of one timing relay due to a wheel of the car having departed from the associated section 5|, and the closing of the back contact 66 of the timing relay T1 next in advance due to the same wheel of the car having moved onto the section 5! associated with this latter timing relay.

As shown in the drawings, all parts of the apparatus are in the positions which they normal- 1y occupy when no car is traversing the stretch of track shown in the drawings. That is to say, the track relays D are all deenergized, the timing relays T are all energized, speed control lever S occupies its 8 position, relays A and B are both deenergized, and lever L occupies its p or oif position. Under these conditions, the braking bars are, of course, held in their non-braking positions.

In explaining-the operation of the apparatus as a whole, I will first assume that a car which is moving at a speed of more than 8 miles per hour is approaching the stretch of track shown in the drawings, and that it is desired to have the car leave the retarder at a speed of. '7 miles per hour. The operator, therefore, first moves lever L to a position which will cause the braking bars to exert sufficient braking force to slow down the car the necessary amount. That is to say, if the car is a light weight car, he moves lever L to its 10 position, if the car is a medium weight car, he moves lever L to its p or 10 position, and if the car is a heavy car, he moves lever L to its 11 position. When this lever is moved to any one 'of these positions, fluid pressure is, of course, ad-

mitted to cylinder 4 in the manner previously described to move the braking bars to their effective or braking positions. The operator next moves the speed control lever S to its s position, which is the position corresponding to a leaving speed or control speed of 7 miles per hour. As the car moves through the retarder, each time a wheel of the car moves onto one of the control sections 5|, the associated track relay D will become energized and will deenergize the associated timing relays T1 and T2, but as long as the speed of the car is above 8 miles per hour, none of. the timing relays T1 or T2 will remain deenergized long enough to close its back contact 6% or 65. Relays A and B will therefore both remain deenergized and the car retarder will therefore continue to slow down the car. As soon, however, as the car has been slowed down by the car retarder to a speed which is equal to or less than 8 miles per hour, and a wheel of the car traverses one of the control sections 5!, the associated timing relay T2 will close its back contact 65, and relay B will then become energized. When relay B becomes energized, the pressure of the fluid supplied to cylinder 4 of motor M will become decreased in the manner previously described so that the braking force exerted by the braking bars will then be less than that which was previously exerted by the braking bars. The braking bars, however, will continue to slow down the car until the car speed decreases to 7 miles per hour. When this happens, as soon as a wheel of. the car traverses one of the control sections El, the associated timing relay T1 will then become deenergized and will close its back contact 66, thus causing relay A to become energized. The energization of relay A Will cause the braking bars to move to their non-braking positions in the manner previously described, and it will be apparent, therefore, that no further retardation of the car will take place unless relay A again becomes deenergized and remains deenergized for a suflicient interval of time to cause it to open its front contact 25-25 and close its back on tact 25 while the car is still within the limits of the car retarder. Due to the slow releasing characteristics of relay A previously pointed out, this can only happen in the event that the car accelerates to a speed which is greater than '7 miles per hour. Assuming the car does this, then as soon thereafter as the timing relay T1 which last became deenergized for a time interval of sufiicient duration to cause it to close its back contact 66 again becomes energized, relay A will become deenergized and will subsequently remain deenergized, because under these conditions, none of the timing relays T1 will now become deenergized long enough to close its back contact 66. Relay A will therefore open its front contact 2525 and will close its back contact 25-2 5 thus restoring the braking bars to their braking positions. If, when the braking bars are restored to their braking positions the car speed is then below 8 miles per hour, none of the timing relays T2 will then be energized so that relay B will be energized and the braking bars will therefore exert the same braking force which they exerted when the car speed decreased below 8 miles per hour. If, however, when the braking bars are restored to their braking positions the car speed is then above 8 miles per hour, or subsequently increases to a speed which is greater than 8 miles per hour, so that none of. the timing relays T2 are then energized, relay B will then be deenergized and the braking bars will then exert a braking force corresponding to the position which lever L then occupies.

' I will now assume that with the braking bars in their braking positions, the operator moves speed control lever S to its s position instead of its 3 position, in order to slow down a car which is approaching the retarder at a relatively high speed to the lowest speed for which the apparatus is designed. Under these conditions, the op eration of the apparatus will be similar to that just described with the exception that since contacts 52 and 53 of lever S are now closed, when a track relay D becomes energized and deenergizes the associated timing relays T1 and T2, it will at the same time complete the shunt circuit for the associated timing relays, thus increasing the length of time these relays must be deenergized before they will close their back contacts. It will be seen, therefore, that when lever S occupies its 8 position, the timing relays T2 and T1 will then release their armatures at a car speed of 5 and 4 miles per hour, respectively, with the result that the braking force exerted on the car will become decreased when the car speed decreases to 5 miles per hour, and the braking bars will be automatically moved to their non-braking positions when the car speed has been decreased to 4 miles per hour.

Referring now to Fig. 2, as here shown, the valves V and V instead of being controlled in part by relay A in the manner shown in Fig. 1, are controlled in part by two relays A and A in such manner that, when both of these relays are deenergized, the operation of the valves V and V for all positions of lever L will be the same as the operation of these valves in Fig. 1 when relay A is deenergized; and that, when either one of these relays becomes energized, the operation of these valves for all positions of lever L will then be the same as the operation in Fig. 1 when relay A becomes energized. The circuits over which the valves V and V are controlled when relays A and A are both deenergized are similar to the corresponding circuits over which these valves are controlled in Fig. 1 when relay A is deenergized, with the exception that each of these circuits includes in place of back contact 25-25 of relay A, a back contact 25-25 of relay A and a back contact 2525 of relay A connected in series; and the circuit over which valve. V is controlled when relay A becomes energized is similar to that over which this valve is controlled in Fig. 1 when relay A becomes energized, with the exception this this circuit includes in place of front contact 25-25 of relay A, front contact 25Z5' of relay A while the circuit over which valve V is controlled in Fig. 2 when relay A becomes energized is similar to that over which valve V is controlled in Fig. 1 when relay A becomes energized, with the exception that this latter circuit includes in place of front contact 2525 of relay A, back contact 25--25 of relay A and front contact 25---25 of relay A It is believed that since the circuits over which the valves V and V are controlled in Fig. 2 differ from those over which these valves are controlled in Fig. 1 only in the manner just pointed out, these circuits will be apparent from the foregoing description and from an inspection of the drawings without further detailed description. It is also believed that since the operation of the valves for all positions of lever L in Fig. 2 is similar to that described in connection with Fig. 1 except for the differences above pointed out, the operation of these valves when lever L is moved to its different positions will be understood from the foregoing and from an inspection of the drawings without further description.

Referring now to the speed responsive means for controlling the relays B, A and A this means in the form here shown comprises a plurality of track relays D1 D1 etc. one of which is associated with each control section 5! but the last, and a track relay D which is associated with the last control section. The relays D1 D1 etc. are similar relays, and each of these relays is provided with two opposing magnets 10 and ll which jointly control a back contact 5555 and three front contacts 55--55 T2 and T3. The magnet 10 of each relay D1 is more powerful than the magnet 1|, and the parts are so proportioned that, when the. magnet it of a relay becomes en-- ergized, the relay will open its back contact and close its front contacts, and that, after the magnet 10 of a relay once becomes energized the back contact of the relay will remain open and the front contacts will remain closed until the magnet 15 again becomes deenergized, even though the magnet subsequently becomes energized. The function of the magnet M will become apparent as the description proceeds.

The winding of each magnet H! is connected in a track circuit which includes in addition to the associated control section 5|, the rail l contact 54 of lever S and a battery F. The winding of each magnet H with the exception of the magnet 1| of relay D1 is provided with a pickup circuit which includes the front contact 13 of the associated relay, the front contact 12 of the relay next in advance, a common wire 14, battery F and a common wire "l5. The Winding of magnet H of relay D1 is provided with a pickup circuit which includes the front contact 13 of relay D1 front contact 12 of relay D common wire [4, battery F and common wire 15.

Track relay D is similar to the relays D D etc. shown in Fig. 1, and is provided with a track circuit which is similar to that for the magnet 10 of each of the relays Du, D1 etc.

With the track relays D1, D1 etc. arranged in the manner just described, it will be apparent that, when contact 54 of lever S is open, or when this contact is closed and no car is traversing the stretch of track shown in the drawings, the magnets Hl and H of each of the relays D1", D1 etc. will be deenergized, and relay D will also be deenergized. When, however, contact 54 of lever S is closed, each time a car wheel moves onto any one of the sections 5| but the section 5| the magnet 10 of the associated track relay will become energized, and will subsequently remain energized, until the car wheel leaves the section, and each time a car wheel moves onto the section 5| the track relay D will become energized and will subsequently remain energized until the car wheel departs from this section. When the magnet 10 of a track relay becomes energized, the relay will open its back contact and close its front contacts, and when the magnet 70 subsequently becomes deenergized, the relay will ordinarily immediately open its front contacts and close its back contact. If, however, a relay fails to open its front contacts and close its back contact immediately when the car wheel leaves the associated section 5|, due, for example, to leakage current supplied to the magnet 19, or to residual magnetism, then as soon thereafter as the relay next in advance closes its front contact 12, the circuit for the magnet 1| of the relay which failed to open its front contacts will become closed and will thus cause this magnet to become energized,

and the energiz'ation of this magnet will pull the front contacts open, thus causing the front con tacts to open almost as quickly as they would have opened if there had been no leakage current or residual magnetism. A similar action will take place if relay D1 has not opened its front contacts when relay D becomes energized. If the magnet 10 of a track relay becomes energized while the magnet l0 of the relay next in advance is energized, the resultant closing of the circuit for the magnet ll of the relay in rear will not affect the relay in rear, since the magnet H is not strong enough to cause the relay to open its front contacts under these conditions, and the fact that the magnet ll for the relay in the rear is energized will assist in causing such relay to open its front contacts quickly when its magnet 15 subsequently becomes deenergized. It follows, therefore, that with the relays D1 constructed and arranged in the manner shown in Fig. 2, these relays will operate without lag, and the time interval during which the front contacts of the relays remain closed and the back contacts remain open will depend positively on the speed of the car.

Associated with each track relay D1 is a timing relay designated by the reference character T with a suitable distinguishing exponent. The timing relays T T etc. are similar to the relays Tz Tz etc. shown in Fig. l and have the same slow releasing characteristics as the relays Te Tz etc. Each timing relay T as shown in Fig. 2 is provided with a pickup circuit which includes a back contact 55-,55 of the associated track relay D1, wire 6%, battery E, and wire 62. Each timing relay T is also provided with a shunt circuit which includes front contact 55---55 of the associated track relay D1, an associated one of a plurality of resistors R, wire 64, contact 53 of lever L, and a wire 62. It will be seen, therefore, that when none of the magnets Ill of the track relays D are energized, as when contact 55 of lever S is open, or when contact 54 is closed and no car is traversing the stretch of track shown in the drawings, all of the timing relays T will be energized; but that, when contact 54 of lever S is closed and a car is traversing the stretch of track shown in the drawings, each time a car wheel moves onto one of the control sections 5|, and causes the magnet N1 of the associated track relay D to become energized, the timing relay controlled by such track relay will become deenergized for a time interval which depends upon the speed of the car. If the speed of the car is sufficiently slow so that this time interval is longer than the release time of such timing relay T, this timing relay will close its back contact 55, but if the speed of the car is not sufficiently slow so that this time interval'is longer than the'release time of this timing relay, this timing relay will not close its back contact 29. The release times of the timing relays T depend upon whether speed control lever S occupies its s or 8 position, and it follows that these relays will close their back contacts at one car speed when the lever S occupies its 8 position and at another car speed when the lever S occupies its 8 position.

Relay B is controlled by the timing relays T T etc. in exactly the same manner that this relay is controlled by the timing relays T2, Ta etc. in Fig. 1.

Relay A is controlled by the timing relays T T T etc. and by lever S by virtue of a plurality of pickup circuits each of which includes a battery G, a back contact 65 of a difierent one of the timing relays and a contact 52--52 of lever S. It will be seen, therefore, that when lever S occupies either its 8 or its s position or when all of the timing relays T T etc. are energized, relay A will be deenergized, but that when lever S is moved to its 3 position and any one of the timing relays becomes deenergized and remains deenergized for a suflicient interval of time to close its back contact 65, relay A will become energized. Due, however, to the slow pickup characteristics of this relay previously pointed out, this relay will not open its back contact 25-25 and close its front contact 2525 unless the back contact 65 which causes this relay to become energized remains closed for a time interval which is longer than the pickup time of this relay. Relay A is made sufficiently slow releasing so that, when a car is traversing the stretch of track shown in the drawings at a speed which is just slow enough to cause the timing relays T to successively close their back contact 65 when the lever S occupies its s position, this relay will bridge the interval of time which will elapse under these conditions between the opening of the back contact 65 of one timing relay due to a wheel of the car having departed from the associated control section 5|, and the closing of the back contact 65 of the timing relay T next in advance due to the same wheel of the car having moved onto the section 5| associated with this latter timing relay.

Relay A is likewise controlled by the timing relays T T T etc. and by lever S by virtue of a plurality of parallel pickup circuits each of which includes battery G, a back contact 65 of a different one of the timing relays T and contact 52--52 of speed control lever S. It will be seen, therefore, that when lever S occupies either its 8 or s positions or when all of the timing relays T are energized, relay A will be deenergized, but that, when lever S occupies its s position and any one of the relays T becomes deenergized and closes its back contact 65, relay A will become energized but will not open its back contact 25-45 and close its front contact unless the contact 65 which causes this relay to become energized remains closed for a time interval which is longer than the pickup time of this relay. Relay A is made sufficiently slow releasing so that, when a car is traversing the stretch of track shown in the drawings at a speed which is just slow enough to cause the timing relays T to suecessively close their back contacts 65 when lever S occupies its 8 position, this relay will bridge the interval of time which will elapse under these conditions between the opening of the back contact 65 of one timing relay due to the wheel of the car having departed from the associated control section 5!, and the closing of the back contact 65 of the timing relay T next in advance due to the same wheel of the car having moved onto the section 5! associated with this latter timing relay.

As shown in the drawings, all parts of the apparatus are in the positions which they normally occupy when no car is traversing the stretch of track shown in the drawings. That is to say, the magnets 10 and H of the timing relays T are all deenergized, track relay D is deenergized, the timing relays T are all energized, speed control lever S occupies its s position, relays B, A and A are all deenergized, lever L occupies its 13 position, valve V is energized and valve V is deenergized. With valve V energized and valve V deenergized the braking bars are held in their non-braking positions by the biasing spring 20.

In explaining the operation of the apparatus as a whole I will assume that a car is approaching the car retarder from the left at a relatively high speed that the operator wishes to slow the car down to a speed corresponding to the s position of the speed control lever. To do this, he will move the lever L to the proper braking position in the manner previously described and will move the speed control lever S to its 5 position. As the car moves through the retarder, each time a wheel of the car moves onto one of the control sections 5|, the magnet IS of the associated track relay D will become energized and will deenergize the associated timing relay T, but as long as the speed of the car is above the speed at which the timing relays T are adjusted to release their armatures, which speed is somewhat higher than that corresponding to the s position of the lever, the relays B, A and A will all remain deenergized and the car retarder will continue to slow down the car. As soon, however, as the car has been slowed down by the car retarder to the speed at which the timing relays T are adjusted to release their armatures and a wheel of the car traverses one of the control sections 5!, the associated relay T will close its back contact 65 and, when this happens, the pickup circuits for relay B and relay A controlled by such contact will become closed. Relay B will therefore immediately pick up, which will cause the braking force exerted by the braking bars to decrease in the manner described in connection with Fig. 1. Relay A however, will not pick up until the car has been slowed down to the control speed corresponding to the s position of the speed control lever S, and a car wheel has traversed one of the control sections 5|, because, for all speeds above this control speed, none of the contacts 65 of the timing relays T will remain closed for a time interval which is equal to or greater than the pickup time for this relay. If, however, the car has slowed down to this control speed, relay A will then pick up and the braking bars will then be moved to their non-braking positions in the manner previously described, and under these conditions no further retardation of the car will take place unless relay A again becomes deenergized and remains deenergized for a time interval which is sufiiciently long to cause this relay to release its armature while the car is still within the limits of the retarder. Due to the slow release characteristics of relay A previously pointed out, this can only happen in the event that the car accelerates to a speed which is greater than that corresponding to the s position of the speed control lever S. Assuming that the car does this, then as soon thereafter as the timing relay T which last became deenergized for a time interval of sufiicient duration to cause relay A to pick up its armature again becomes energized, relay A will again become deenergized, and its armature will subsequently remain open, because, under these conditions, none of the other timing relays will now become deenergized for a long enough interval of time to cause relay A to again close its armature. Relay A will therefore open its front contact 25---25 and close its back contact 2525 thus restoring the braking bars to the braking positions. The braking bars, however, will not exert the full braking force corresponding to the position which the lever then occupies unless the car speed has increased to a speed at which none of the timing relays will close their back contact 65, because as long-as the speed of the car is below this speed, relay B will become energized each time a timing relay closes its back contact and as long as this relay remains energized the braking bars will exert a reduced braking force on the car. If, however, the car speed does increase above that at which the relays T close their back contacts 65, relay B will then become deenergized and the braking bars will then exert their full braking force corresponding tothe position which the lever L then occupies.

I will now assume that with the braking bars in their braking positions, the operator moves lever S to its s position instead of its 8 position, in order to slow down a car which is approaching the retarder at a relatively high speed to the slowest speed for which the apparatus is designed. Under these conditions, the operation of the apparatus will be similar to that just described with the exception that, under these conditions, the shunt circuits for the timing relays will now be rendered effective, so that these relays will release their armatures at a slower car speed, and with the further exception that the relay A will now be effective for controlling the braking apparatus instead of the relay A As was previously pointed out, the relay A has a slower pickup time than the relay A and it will be apparent, therefore, that when lever S occupies its 10 position, the retarder will slow down the car to a lower car speed, as will readily be understood from the foregoing without further description.

One advantage of braking apparatus embodying my invention is that the retardation force exerted by the apparatus, and thereby the rate of retardation of a car which is being retarded by the apparatus, is decreased as the speed of the car approaches control speed, thus permitting full release of the retarder at a value nearer that of the nominal control speed after the car speed has actually reached control speed. The efiect of this operation is to cause a more accurate control of the car speed, since this control is dependent, to a large extent, upon the length of time required to fully release the retarder, and the rate of retardation during this release. This is particularly important when the full braking force is applied to a car at a low control speed.

Although I have herein shown and described only two forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims Without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is: a

1. In combination, a stretch of railway track, fluid pressure operated braking apparatus for retarding the speed of a car traversing said stretch, means for supplying said apparatus with fluid at different pressures to cause said apparatus to exert different braking forces, and means controlled by the speed of a car traversing said stretch for reducing the pressure of the fluid supplied to said apparatus a first predetermined amount when the speed ot the car has decreased to a predetermined speed and for subsequently reducing said pressure a second predetermined amount.

2. In combination, a stretch of railway track, fluid pressure operated braking apparatus for retarding the speed of a car traversing said stretch, means for supplying said apparatus with fluid at different pressures to cause said apparatus to exert different braking forces, and means controlled by the speed of a car traversing said stretch for reducing the pressure of the fluid supplied to said apparatus. a first predetermined amount when the speed of the car has decreased to a first predetermined speed and for subsequently reducing said pressure a second predetermined amount when the speed of the car has decreased to a second predetermined speed.

3. In combination, a stretch of railway track, a fluid pressure operated car retarder, and means controlled by a car passing through said car retarder for controlling the pressure of the fluid supplied to said car retarder to control the braking force exerted on the car by the car retarder in such manner that the braking force exerted on said car will decrease a first predetermined amount when the car speed decreases to a first predetermined speed and a second predetermined amount when the car speed decreases to a second predetermined speed which is less than said first predetermined speed.

4. In combination, a stretch of railway track, a fluid pressure operated car retarder, and means controlled by a car passing through said car retarder for controlling the pressure of the fluid supplied to said car retarder to control the braking force exerted on the car by the car retarder in such manner that the braking force exerted on said car by said car retarder will decrease a predetermined amount when the car speed decreases to a selected one of a plurality of predetermined speeds and will decrease to zero when the car speed decreases to a second predetermined speed which is less than said first selected predetermined speed.

5. In combination, a stretch of railway track, a braking bar extending parallel with one of the rails of said stretch and adapted to be at times moved toward the associated rail for engagement with the wheels of a passing car to retard the speed of the car, operating means for said braking bar, a series of relays .adapted to be successively operated by the wheels of a car traversing said stretch for time intervals which depend on the speed of the car, a first series of timing relays each controlled by a different one of said first mentioned relays, a second series of timing relays each controlled by a different one of said first mentioned relays and each being adapted to operate at the expiration of a different time interval from that at which the corresponding relay of the first series is adapted to operate, and means controlled by said timing relays for controlling said operating means.

6. In combination, a stretch of railway track, a braking bar extending parallel with one of the rails of said stretch and adapted to be at times moved toward the associated rail for engagement with the wheels of a passing car to retard the speed of the car, a series of contacts, means controlled by a car traversing said stretch for successively operating said contacts for time intervals which depend upon the speed of the car, a first relay controlled by said contacts in such manner that said first relay will become operated if and only if one of said contacts remains operated for more than a predetermined time interval, a second relay controlled by said contacts in such manner that said second relay will become operated if and only if one of said contacts remains operated for a time interval which is somewhat longer than that required to cause said first relay to operate, and means controlled in part by said two relays for controlling the braking action of said braking bar.

'7. In combination, a stretch of railway track, a braking bar extending parallel with one of the rails of said stretch and adapted to be at times moved toward the associated rail for engagement with the wheels of a passing car to retard the speed of the car, a series of contacts, means controlled by a car traversing said stretch for successively operating said contacts for time intervals which depend upon the speed of the car, a first relay controlled by said contacts in such manner that said first relay will become energized if and only if one of said contacts remains operated for more than a predetermined time interval, a second relay controlled by said contacts in such manner that said second relay will become energized if and only if one of said contacts remains operated for a time interval which is somewhat longer than that required to cause said first relay to operate, pressure responsive means for operating said braking bar, manually controlled means effective when said first and second relays are both deenergized for supplying said pressure responsive means with fluid at different pressures to cause said braking bar to exert different braking forces, means effective when said first relay becomes deenergized for decreasing the pressure of the fluid supplied to said pressure responsive means to decrease the braking force exerted by said braking bars, and means effective when said second relay becomes energized for cutting off the supply of fluid pressure to said pressure responsive means.

8. In combination, a stretch of railway track, a fluid pressure operated car retarder for retarding the speed of a car traversing said stretch, two relays, manually controlled means effective when both of said relays are deenergized for supplying said car retarder with fluid at different pressures to cause said car retarder to exert different braking forces, means effective when a first one of said relays becomes energized for decreasing the pressure of the fluid supplied to said car retarder, means effective when the other relay becomes energized for cutting off the supply of fluid to said car retarder, and means controlled by the speed of a car traversing said stretch for selectively energizing said relays.

9. In combination, a stretch of railway track, a fluid pressure operated car retarder for retarding the speed of a car traversing said stretch, two relays, manually controlled means effective when both of said relays are deenergized for supplying said car retarder with fluid at different pressures to cause said car retarder to exert different braking forces, means effective when a first one of said relays becomes energized for decreasing the pressure of the fluid supplied to said car retarder, means effective when the other relay becomes energized for cutting off the supply of fluid to said car retarder, means for energizing said first relay when and only when the speed of a car which is traversing said stretch is below a predetermined speed, and means for energizing said other relay when and only when the speed of a car which is traversing said stretch is below a speed which is somewhat lower than said predetermined speed.

10. In combination, a stretch of railway track, a fluid pressure operated car retarder for retarding the speed of a car traversing said stretch, two relays, manually controlled means effective when both of said relays are deenergized for supplying said car retarder with fluid at different pressures to cause said car retarder to exert different braking forces, means effective when a first one of said relays becomes energized for decreasing the pressure of the fluid supplied to said car retarder, means effective when the other relay becomes energized for cutting off the supply of fluid to said car retarder, means for energizing said first relay when the speed of a car which is traversing said stretch decreases to a selected one of a plurality of predetermined speeds, and means for energizing said other relay when the speed of a car which is traversing said stretch decreases to a speed which is somewhat less than the selected speed at which said first relay releases.

11. In combination, a stretch of railway track, a braking bar located in the trackway adjacent one of the rails of said stretch and movable toward and away from such one rail into braking and non-braking positions, a series of short insulated control sections formed in one rail of said stretch, a series of track relays; a plurality of track circuits each including a different one of said control sections, the opposite rail, a different one of said track relays and a source of current; i

a first series of slow releasing timing relays one controlled by a back contact of each track relay, a second series of slow releasing timing relays one controlled by a back contact of each track relay and each having a longer release time than the release time of the corresponding relay of the first series, and means controlled by said timing relays for controlling said braking bar.

12. In combination, a stretch of railway track, a braking bar located in the trackway adjacent one of the rails of said stretch and movable toward and away from such one rail into braking and non-braking positions, a series of short insulated control sections formed in one rail of said stretch, a series of track relays; a plurality of track circuits each including a different one of said control sections, the opposite rail, a different one of said track relays and a source of current; a first series of slow releasing timing relays one controlled by a back contact of each track relay, a second series of slow releasing timing relays one controlled by a back contact of each track relay and each having a longer release time than the release time of the corresponding relay of the first series, a first slow releasing control relay controlled by the timing relays of the first series, a second slow releasing control relay controlled by the timing relays of the second series, and means controlled by said control relays for controlling said braking bar.

13. In combination, a stretch of railway track, a braking bar located in the trackway adjacent one of the rails of said stretch and movable toward and away from such one rail into braking and non-braking positions, a series of short insulated control sections formed in one rail of said stretch, a series of track relays; a plurality of track circuits each including a different one of said control sections, the opposite rail, a different one of said track relays and a source of current; a first series of slow releasing timing relays one controlled by a back contact of each track relay, a second series of slow releasing timing relays one controlled by a back contact of each track relay and each having a longer release time than the release time of the corresponding relay of the first series, a first control relay provided with a plurality of pickup circuits each including a back contact of a different one of the timing relays of the first series, a second control relay provided with a plurality of pickup circuits each including a back contact of a different one of the timing relays of the second series, and means controlled by said control relays for controlling said braking bar.

14. In combination, a stretch of railway track, a braking bar located in the trackway adjacent one of the rails of said stretch and movable to- Ward and away from such one rail into braking and non-braking positions, a series of short insulated control sections formed in one rail of said stretch, a series of track relays; a plurality of track circuits each including a different one of said control sections, the opposite rail, a different one of said track relays and a source of current; a first series of slow releasing timing relays one controlled by a back contact of each track relay, a second series of slow releasing timing relays one controlled by a back contact of each track relay and each having a, longer release time than the release time of the corresponding relay of the first series, a first controlrelay provided with a plurality of pickup circuits each including a back contact of a different one of the timing relays of the first series, a second control relay provided with a plurality of pickup circuits each including a back contact of'a different one of the timing relays of the second series, a fluid pressure operated device for operating said braking bar, means effective when said control relays are both deenergized for supplying said device with fluid at different pressures, means effective when said first control relay becomes energized for decreasing the pressure of the fluid which is supplied to said device a predetermined amount, and means effective when said second control relay becomes energized for cutting off the supply of pressure to said device.

15. In combination, a stretch of railway track, a fluid pressure operated car retarder for controlling the speed of a car traversing said stretch, a first series of contacts, means controlled by a car traversing said stretch for successively closing the contacts of said first series for time intervals which depend upon the speed of the car, a second series of contacts one for each contact of the first series, means for closing each contact of the second series if the corresponding contact of the first series remains closed for more than a predetermined time interval and for subsequently maintaining the contact closed until the corresponding contact of the first series, opens, a speed control lever having an off position and a plurality of on positions, a quick to pick up, slow to release relay, a plurality of circuits for said quick to pick upjslow to release relay each including a different one of the contacts of said second series, a first and a second slow to pick up and slow to release relay, a plurality of circuits for said first slowto pick up and slow to release relay including a different one of the contacts of said second series and a contact of said lever which is closed in one of its on positions, a plurality of circuits for said second slow to pick up and slow to release relay including a different one of the contacts of said second series and a contact of said lever which is closed in another of its on positions, and means controlled by said three relays for controlling the supply of fluid pressure to said car retarder.

16. In combination, a stretch of railway track, a fluid pressure operated car retarder for controlling the speed of a car traversing said stretch, a first series of contacts, means controlled by a car traversing said stretch for successively closing the contacts of said first series for time in-' tervals which depend upon the speed of the car, a second series of contacts one for each contact of the first series, means for closing each contact of the second series if the corresponding contact of the first series remains closed for more than a predetermined time interval and for subsequently maintaining the contact closed until the corresponding contact of the first series opens, a speed control lever having an off position and a plurality of on positions, aquick to pick up, slow to release relay, a plurality of circuits for said quick to pick up, slow to release relay each including a different one of the contacts of said second series, a first and a second slow to pick up and slow to release relay, a plurality of circuits for said first slow to pick up and slow: to release relay including a different one of the con-' tacts of said second series and a contact of said lever which is closed in one of its on positions, a plurality of circuits for said second slow to pick up and slow to release relay including a different one of the contacts of said second series and a contact of said lever which is closed in another'of its on positions, manually controlled means effective when all of said relays are deenergized for supplying said car retarder with fluid at different pressures to cause said car retarder to exert different braking forces, means effective when said quick to pick up, slow to release relay becomes energized for reducing the pressure of the fluid supplied to said car retarder a predetermined amount, and means effective when either of said slow to pick up and slow to release relays becomes energized for cutting off the supply of fluid pressure to said car retarder.

1'7. In combination, a stretch of railway track, a braking bar located in the trackway adjacent one of the rails of said stretch and movable toward and away from said one rail into braking and non-braking positions, a series of relatively short insulated control sections formed in one rail of said stretch, a series of track relays one for each control section but the last, each said relay of said series being provided with a main magnet for picking up the relay and an auxiliary magnet for assisting the release of the relay, a track relay associated with the last control section, a plurality of track circuits one for the main magnet of each relay of the series and each including the associated control section, the opposite rail of the stretch and a source of current; a circuit for the auxiliary magnet of each track relay of the series but the last including a front contact of the relay and a front contact of the relay next in advance, a

circuit for the auxiliary magnet for the last relay of the series including a front contact of the relay and a front contact of the track relay associated with the last control section; a track circuit for the track relay associated with the last control section including the last control section, the opposite rail of the stretch and a source of current; and means controlled by said series of track relays for controlling and non-braking positions, a series of relatively short insulated control sections formed in one rail of said stretch, a series of track relays one for each track section but the last and each provided with two opposing magnets one of which is stronger than the other, the parts be--' ing so proportioned that when the one magnet of a track relay becomes energized the relay will close its front contacts and open its back contacts and that if the other magnet becomes energized while one magnet is energized the front contacts of the relay will remain closed; a plurality of track circuits each including the one magnet of a different one of the track relays of said series, a different one of said control sections, the opposite rail of the stretch, and a source of current; a circuit for the other magnet of each of the track relays of the series but the last including a front contact of the relay and a front contact of the relay next in advance; a track relay associated with the last control section of the series, said relay being provided with a track circuit which includes the associated track section, the opposite rail of the stretch, and a source of current; a circuit for the other magnet of the last track relay of the series including a front contact of the relay and a front contact of the track relay associated with the last track section, and means controlled by said series of track relays for controlling said braking bar.

19. In combination, a stretch of railway track, a fluid pressure operated car retarder for retarding the speed of a car traversing said stretch, two relays, manually controlled means effective when both of said relays are deenergized for supplying said car retarder with fluid at different pressures to cause said car retarder to exert different braking forces, means effective when a first one of said relays becomes energized for decreasing the pressure of the fluid supplied to said car retarder, means effective when the other relay becomes energized for cutting off the supply of fluid to said car retarder, and means for selectively energizing said relays.

20. In combination, a stretch of railway track, a series of relatively short insulated control sections formed in one rail of said stretch, a series of track relays one for each control section but the last, each said relay of said series being provided with a main magnet for picking up the relay and an auxiliary magnet for assisting the release of the relay, a track relay associated with the last control section, a plurality of track circuits one for the main magnet of each relay of the series and each including the associated control section, the opposite rail of the stretch and a source of current; a circuit for the auxiliary magnet of each track relay of the series but the last including a front contact of the relay and a front contact of the relay next in advance, a circuit for the auxiliary magnet for the last relay of the series including a front contact of the relay and a front contact of the track relay associated with the last control section; a track circuit for the track relay associated with the last control section including the last control section, the opposite rail of the stretch and a source of current; and traflic governing means controlled by said series of track relays for controlling said braking bar.

21. In combination, a stretch of railway track,

a series of relatively short insulated control sections formed in one rail of said stretch, a series of track relays one for each track section but the last and each provided with two opposing magnets one of which is stronger than the other, the parts being so proportioned that when the one magnet of a track relay becomes energized the relay will close its front contacts and open its back contacts and that if the other magnet becomes energized while one magnet is energized the front contacts of the relay will remain closed; a plurality of track circuits each including the one magnet of a different one of the track relays of said series, a different one of said control sections, the opposite rail of the stretch, and a source of current; a circuit for the other magnet of each of the track relays of the series but the last including a front contact of the relay and a front contact of the relay next in advance; a track relay associated with the last control section of the series, said relay being provided with a track circuit which includes the associated track section, the opposite rail of the stretch, and a source of current; a circuit for the other magnet of the last track relay of the series including a front contact of the relay and a front contact of the track relay associated with the last track section, and traffic governing means controlled by said series of track relays.

22. In combination, a stretch of railway track, fluid pressure operated braking apparatus for retarding the speed of a car traversing said stretch, means for supplying said apparatus with fluid at a selected one of a plurality of predetermined pressures, and means for automatically reducing the pressure of the fluid supplied to said apparatus a first predetermined amount if the speed of the car which is traversing said stretch decreases to a speed which is between a first and second predetermined speeds and for further reducing said pressure or restoring it to its initial value if the car speed subsequently decreases below said second predetermined speed or increases above said first predetermined speed.

23. In combination, a stretch of railway track, fluid pressure operated braking apparatus for retarding the speed of a car traversing said stretch, means for supplying said apparatus with fluid at a selected one of a plurality of predetermined pressures, and means for automatically reducing the pressure of the fluid supplied to said apparatus a first predetermined amount if the speed of the car which is traversing said stretch decreases to a speed which is between a first and second predetermined speeds, for reducing said pressure a second predetermined amount if the speed of the car decreases below a second predetermined speed, for again increasing said pressure the amount it was reduced when the speed of the car decreased below said second predetermined speed if the speed of the car subsequently increases above said second predetermined speed, and for restoring said pressure to its initial value if the speed of the car subsequently increases above said first predetermined speed.

HERBERT L. BONE.

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