US1925252A - Train control system - Google Patents

Description

Sept. 5, 1933. A. E. HUDD TRAIN CONTROL SYSTEI Filed lay 27 1927 4 Sheets-Sheet 1 Inuen ur ElleiE'P-"Z'nas Hudi Sept. 5, 1933. A. E. HUDD 1,925,252

TRAIN CONTROL SYSTE Filed Ilay 27 Y 1927 4 Sheets-Sheet 2 nUEnDI" Elfrez .E1-@Huid Sept. 5, 1933. A. rs.v HUDD TRAIN CONTROL SYSTEM Filed May 27., 1927 0; li'rglgrrl 4 Sheets-Sheet 3 Inval-111:1" Hlfd EWSTI'HLLEZEL Sept. 5, 1933. A, E, HUDD TRAIN com'noz. sYsrsu Filed May 27 1927 4 Sheets-Sheet 4 [nuen nr ZfedErmHudi Al EEG Patented Sept. 5, 1933 UNITEDl STAT-ES TRAIN coNTRoL SYSTEM Alfred E. Hudd, Evanston, Ill., assignor, by mesne assignments, to Associated Electric Laboratories, Inc., Chicago, Ill., a corporation of Dela- Ware Application May 2'?, 1927. Serial No. 194,587

24 Claims.

The presen-t invention relates in general to automatic train control systems, but is particularly concernedwith the provision of an intermittent inductive automatic trai-n stop arrangement provided with facilities for imposing speed control features not ordinarily found in the commonly known train stop systems. v

In all systems in this category known to applicant the engineman, if alert, may forestall the automatic application of brakes on passing a signal at caution vor danger and after having done so, he may continue at full speed if he so desires without any further check until he comes to the next signal. signal given, either visual or audible, to remind the engineman that he is in -or approaching a danger zone, or whether he has or has not operated his foresta-lling device at the last signal he has passed, or whether it was the one before the last.

Among the more important features provided for in the-present system are: a forestalling device as in other systems; the provision of audible and visual indications given when a signal at caution or danger is being passed; means for enforcing a time interval between two successive acknowledgment operations, which enables a speed control to be established when approaching stop signals, and which will automatically cause the application of brakes if the train exceeds a desired low speed; means for giving a clear indication upon passing a signal at clear by a positive action of the apparatus; and of a simple and rugged detecting device operated from the locomotive cab to enable the train control apparatus to be reset to normal only when the train has come to a complete standstill.

There are other miscellaneous less important features not specifically mentioned, but which will be brought out in the specification and claims.

The invention is herein disclosed in four sheets ci drawings; sheets l. and 2, (Figs. l and 2) should be laid out adjacent to each other with the corresponding parts in alignment, While sheet 3 (Figs. 3 and 4) should be placed directly below sheet 2, with the corresponding parts in alignment. Sheet `4, comprising Fig. 5, discloses a diagram and associated track circuits and is complete in itself.

Considering the iigures more in detail, Fig. 1 discloses a standard locomotive brake valve equipped with a special operating handle and a cin-operating pneumatic applicator and controlling valve.

Fig. 2 discloses a unit comprising an electro pneumatic valve EP and miscellaneous other associated pneumatic devicessignals and air reservoirs. The major part of the apparatus is shown in section so that the relation between the various component parts may be more readily shown and described.

Furthermore, there is noV Fig. 3 shows a stop detector in normal relation to a vehicle wheel.

4 is a View of the impulse pickup relay equipment suspended from a tender frame. The shown partly in cross-section as is also an associated roadside magnet.

The various elements in Figs. l and 2 areV shown in their normal position and it will be observed that when in this position the electropneumatie valve EP is energized over a circuit extending from a battery, through the winding` of the EP valve magnet, conductor 48, contacts 21 of the pickup relay, conductor 48', and through the detector rod and associated conductor to ground. With the EP valve energized valve 6 is held closed. Under these circumstances the air chamber A of Fig. l and the communicating pipe 3 connecting it with the reservoir i3 oi Fig. 2 and the reservoir itself are under full air pressure from the main reservoir (not shown) supplying air to them via needle valve 4. With this state of affairs existing, the main reservoir pressure in chamber A is ample to hold the valve 10 seated'.

The other valves 26, I9 and 28 are normally held in the positions in which they are shown, by air pressure normally applied to the respective air chambers 15, i6, and D. The contacts t8.y are also normally maintained closed, as shown, by air pressure on the diaphragm 31.

Fig. E discloses a stop detector SD in operative relation with a locomotive wheel and which is a pneumatically operated device of the type shown and described in detail in the copending Hudd application, Serial Number 170,048, filed Feb. 21st, i927. This device consists of a pneumatically operable plunger carrying a spherical valve adapted to be opened only when the element 46 is forced into engagement with the wheel while' the wheel is moving, as. described in detail in the application referred to.

Fig. Ll shows a permanent magnet "roadside inductor and a receiver or pick up relay. The structure of the electromagnet inductors are along the same general lines. The structure of the pickup relay is similar to a relay used for the samepurpose in the system disclosed in a co-pending Hudd application bearing Serial No. 139,794, filed Oct. 6, 1926, but the operating and restoring circuits are slightly different. This pickup relay like the one in the former disclosure has a permanent magnet which holds the armature biased to either position to' which it is operated. The relay and its associatedpick-up brushes are suspended from the tender frame by a number of bolts, two of which can be seen in this ligure. It will be observed that a third bolt labeled detector rod is used as a conductive element through which current is supplied to a pair of reset coils 39 of the pick-up relay 'CII and to the EP valve magnet. These reset coils are energized under certain conditions to restore the armature of the pickup relay, as will be described subsequently. The detector rod is turned out of cast iron and, therefore, is very brittle. Should the pick-up relay or the associated structure come info contact with anything with sufficient force to bend the supporting bolts or other- Wise render the equipment useless, the impact will be sufficient to break the relatively brittle detector rod and bring about the deenergization of the electropneumatic valve EP. This will cause an automatic brake application to occur in a manner which will be subsequently made clear.

Fig. 5 shows a diagram illustrating a trackway divided up into a number of blocks or sections with associated block signals at clear, caution, stop, and clear, positions respectively. The brake control curve which should be followed under the conditions indicated is also shown, as are also track circuits for determining the condition of the roadside inductors.

Before going into the description of the various cycles of operation it has been deemed advisable to describe the track circuits and to explain how they accomplish the Various circuit changes to vary the magnetic conditions of the roadside inductors, as required to obtain the desired train controlling operations.

In the illustration given a locomotive is shown travelling towards the right and is in the last complete block section shown. Under these conditions the current normally supplied through the contacts of the three position polarized relay 54 is shunted from the three position polarized relay 53, causing this relay to assume its neutral position. With the relay 53 in neutral position an operating circuit for the three position relay 52 is completed, from the battery associated with relay 53, causing this relay to assume its neutral tures of this relay, the lower track rail, the winding of the three position polarized relay 52, and the upper track rail back to the opposite side of the battery. The current flow to the relay 52 is in the appropriate direction to cause this relay to rotate its armatures in a counter-clockwise direction, into the position in which they are shown.

With the relay 52 in this position a circuit through the distant associated electromagnet trackway element is completed, which extends from the battery associated with the relay 52 to the armatures and lower contacts of this relay, through the distant electromagnet, the lower track rail, through the polarized relay 51, and back to the battery over the upper track rail. The current flow is in the appropriate direction to cause the armatures of the relay 51 to be rotated in a clockwise direction into engagement with their upper contacts.

With the relay 51 in this position it supplies current from the battery at this point, through its armatures and upper contacts, to the associated distant and home electromagnet trackway elements in multiple, and to the lower trackway rail. At the entrance of this block is another three position relay, not shown, through which the battery current flows to the upper trackway rail and back to the other terminal of the battery.

Upon reviewing the trackway circuits, just traced, it will be noted that the roadside inductors, both distant and home, of the blocks having their semaphores in clear position are enerj gized; only the distant roadside inductor of the block having its signal at caution is energized;

while neither the distant or home roadside inductor associated with the block having its signal at stop is energized. The coordinate control of the semaphore blades may be of any customary type, and does not form a part of applicants invention,

With these facts in mind we will now divert our attention to the various cycles of operation which take place as the locomotive passes over the various sections when track conditions are as indicated in Fig. 5.

Passing a signal at clear As shown by the circuit of the diagram disclosed in Fig. 5, on passing a signal at clear the receiver on the locomotive rst passes over a permanent magnet, which deflects the receiver armature 45 and breaks contacts 21, opening the normally established circuit for the electropneumatic valve EP. The electropneumatic valve, upon becoming deenergized drops its armature 29 permitting the associated valve 6 to open. This allows the pressure in chamber A and reser voir B to be reduced, as the openings thru valve 6 and chamber E are very large compared to the air supply thru needle valve 4. After approximately 6 feet of travel, the locomotive receiver passes over the associated electro-magnet roadside inductor which, due to the circuit condition indicated in Fig. 5, resets the armature 45, again closing contacts 21, so that the electropneumatic valve again becomes energized, closing valve 6, and thus restoring the operated apparatus to its original condition. The armature 29, in dropping, also, through the medium of the spring 23, permits spring 22 to break the circuit of the green lamp G and close the circuit of the red lamp R. The green lamp will therefore be momentarily extinguished and the red lamp will be lighted during the brief period during which the electropneumatic valve is deenergized. This momentary signal change serves to indicate to the en-r gineer that he passed a trackway device at clear.

The foregoing operations take place at all clear signals and constitute a self checking or positive action and, unless the train is running at very low speed, the whistle W will 'not be sounded, for the reason that it takes one half second for the chamber E behind the whistle to fill up before the whistle can blow. This arrangement avoids calling the enginemens attention audibly when passing a signal at clear.

Passing a signal at caution Referring again to the diagram of Fig. 5, it will be seen that a pair of roadside magnets is located 500 feet behind each signal location andV that, in addition, there is a pair of magnets xed at the signal itself.

As clearly indicated in the circuit and as previously traced, when a signal at clear is encountered both electromagnets are energized and the apparatus on the locomotive accordingly again functions as heretofore described, when passing the pair at the signal itself, but when the signal is at caution the second electromagnet encountered is deenergized, as indicated; therefore, the electropneumatic valve EP is not restored at the second electromagnet. The deenergized electropneumatic valve, at its contacts 24, opens the normally closed circuit of the green lamp G and at its contacts 25 closes the circuit for the red lamp R. Since on this occasion the reservoir pressure in chamber B is being reduced for a period greater than one half second, the air pressure in chamber E rises suiiciently to cause the whistle W to blow and give the enginemen a further warning of the condition under which he is operating the locomotive. Acknowledgment must be made at this time by the engineman who must hoid the acknowledging plunger AP in operated position until the whistle stops blowing in order to avoid an automatic application o the brakes. When the acknowledging plunger AP is operated it opens valve 26 which connects chamber 16 with atmosphere and also the chamber l5 immediately above valve diaphragm 27. The small orifice 17 thru which the main reservoir pressure is being supplied is not suiiicient to maintain the pressure on top of diaphragm 27 and, therefore, the Valve 28 becomes released. This permits a momentary rush of air from the valve chamber D to pass out thru the pipe 14 onto the disk 15', raising the spring 29 suiiiciently to momentarily close contacts 13. This results in a circuit being established from a battery, through contacts 38, conductor 30, thru contacts 13. conductor 34, and the windings of reset coils 39, and the detector rod to ground. The receiver armature consequently becomes restored to its normal condition and reestablishes the hereinbefore traced circuit of the EP valve magnet.

It will be noted that the movement ol" the acknowledging plunger LP pushes the spring 23 out of engagement with contact spring 22 and that it is held out oi range of spring 22 until armature 29 has been restored to its normal energized condition. The result is that when spring 23 is returned to its normal height by the electropneumatic valve armature the spring 22 remains in engagement with its lower Contact and, therefore, the red light is not changed and remains in a lighted condition until the armature 29 has fallen and picked up again with the plunger .AP released. Only under this condition is the spring 23 permitted to catch the underside of spring 22 and so raise it to its normal position, opening contacts 25 and closing contacts 24.

Since it is only when signals at clear are encountered that the electropneumatic valve EP is deenergized and restored again without the aid of the acknowledging plunger, it follows that the green light can only be restored on passing a signal at "clear-2 Returning to the action of contacts 13, it will be noted that the chamber D is of very low capacity and therefore allows air o sufiicient pra sure to actuate contacts 13 only for a very short duration of time, the opening 18 to the main reservoir being reduced suiciently to prevent anyT rise of pressure in the chamber D when valve 28 is open. For this reason it will be seen that only a momentary closing of contacts 13 can be accomplished at the iirst'inward movement of the plunger AP.

When the plunger is rst operated the chamber D is discharged as is also the reservoir C and the space on top of diaphragm 27. The orice 17 to the main reservoir and the size of the reservoir C are so adjusted that after one actuation of the plunger AP sufficient air pressure cannot be again applied to diaphragm 27 to close valve 28 until chamber C has been recharged. This requires approximately 20 seconds. It follows that a second blast of air cannot be given to close con-V tacts 13 until that amount of delay has taken place.

usual way after passing the iirst encountered pair of magnets, but when the train reaches the signal another impulse is received and again demands acknowledgment.

1f twenty seconds had expired since the rst acknowledgment vwas made, the average speed between the two pairs of inductors was approximately twenty iniles per hour; accordingly a second acknowledgment can be made in the same manner as was the first. However, if the engineman has disobeyed the previous warning and maintained an average speed of over twenty miles per hour he will arrive at the second acknowledgM ing point before the required laps of 2O seconds and an operation of the acknowledging plunger will be without ei'ect. Consequently, due to the capacity of reservoir B and adjustment of needle valve 4, within six seconds after encountering the -ermanent magnet at the signal, the air pressure in the line 3 will have been reduced to ten pounds which a sufficient reduction to permit the main reservoir pressure to overcome the pressure on piston 8 and piston 11 will be actuated to apply the brakes.

The automatic application of the brakes An automatic brake application having once been initiated, either by failure to acknowledge a caution or danger signal, or by having eX- ceeded the speed limit on approaching a stop signal, cannot be annulled until `the train has come to a stand still. The provision made for this control comprises the pneumatic switch PS, having its contacts 38 normally closed by air pressure applied to its diaphragm 31. The spring 32 is so tensioned that this switch will open when the pressure in the line is reduced to ten pounds at which time, it will be recalled, the piston 8 in the applicator releases valve 10 and which is at the stage that the brakes will be automatically applied and the circuit of reset coils 39 broken. As previously described the operation of the acknowledging plunger opens the valve 2S, so that the pressure in the chamber D is released. The release of pressure in chamber D in turn releases the diaphragm 33 and valve 19. With the valve 19 released the admission of main reservoir air.

via the opening 20 will eventually close the stop detector contacts 40, provided that the locomotive is at a complete stand still. This action takes place although the piston 41 of this pneumatic switch normally keeps the contacts 40 open by means of the spring 43. The area of piston 41 and the strength of spring 43 are arranged so that it requires a pressure of at least 70 pounds tacts 40, all as fully described in the co-pending application formerly referred to. The closing of these contacts completes a circuit for energizing the reset coils 39 independently of the contacts 38. This circuit may be traced from a battery, through contacts 40, conductor 34 to the reset coils 30 and ground via the detector rod. As soon as this circuit is closed armature 45 assumes its normal position and the electropneumatic valve is energized over a circuit extending from a battery, thru the electropneumatic valve conductor 48, contacts 21 of the receiver magnet, and the detector rod to ground. The electropneumatic valve therefore is actuated to again close valve 6. Soon thereafter the pressure in line 3 becomes sufficient to restore the piston 8 to its initial position. In this position the air supply to piston 1l is cut oir and the engineman can then release the brakes by manually restoring the handle to running position.

Should the engineman attempt to operate the acknowledging plunger While the train is in motion to effect a release, the valve element 46 will tilt over immediately it touches the Wheel and release the pressure being applied to the stop detector and to the piston 38, so that it is impossible to close contacts While the locomotive is in motion.

What is claimed is:

1. In an automatic train stop mechanism, an electropneumatic valve, a circuit for normally maintaining said valve energized, a paii` of signals, circuits for energizing said signals including a contact operated by said electropneumatic valve, and means for at times preventing the actuation of said valve from operating said contact.

2. In a train control system, a normally ener-- gized electropneumatic brake controlling valve eiective When released to cause a brake applying action to be initiated, signalling means also responsive to such release to give a Warning that the brake applying function has been initiated, means for restoring the electropneumatic valve to its energized condition to prevent the brakes being applied, and other means controlled by said restoring means for preventing the restoration of the electropneumatic valve from changing the responsive condition of the signalling means.

3. In a train control system, a normally energized magnet, means for causing the deenergization of said magnet, means operated responsive to such deenergization to Warn an engineman visually and audibly of the changed condition of the magnet, means controlled by the engineman for causing the reenergization of said magnet, and auxiliary means also operated incidental to the actuation necessary to reenergize said magnet for preventing its reenergization from eX- tinguishing said visual signal means.

4. In a train control system, an inductive pickup device, means for supporting said device on a vehicle, a brake valve control circuit passing thru contacts of said pick-up device normally held closed to prevent a brake application, and a brittle conductor included in said circuit and in the structure connecting the pick-up device With the vehicle,

5. In a train control system, an electropneumatic valve, a normally closed operating circuit for said valve, a train carried relay having contacts thru which. said circuit passes, track-Way elements for operating said relay to cause the same to open and close said circuit, visual means for immediately Warning an engineman when the circuit is broken, time controlled means for further warning the engineman after a certain period of time, manually operable means whereby the engineman, if alert, can cause the relay to again close said circuit, brake applying means effective if the engineman fails to operate said manually operable means and means for preventing the engineman from effecting said circuit closure after the brakes have been applied until the train has come to an absolute stop.

6. In a train control system, an electropneumatic valve, a circuit for maintaining said valve closed, means for breaking said circuit, means operative consequent to the deenergization of said valve to give a signal to this effect, a reservoir and an associated needle valve thru which compressed air is supplied, and a second signal operated by compressed air after the valve has remained deenergized an interval determined by the capacity of said reservoir and adjustment of said needle valve.

'7. In a train control system, a pneumatic brake applicator, a valve normally closed to prevent main reservoir pressure being applied to said applicator, means i'or normally maintaining said valve closed comprising an air line also connected with main reservoir pressure via a needle valve and an electromagnetically closed valve to atmosphere, means for opening said last valve to permit the nrst valve to open after the air pressure in said line has been reduced to a speciiic point, and an auxiliary reservoir also connected to said line and cc-operating With said needle valve to delay the reduction of pressure in said line.

8. Tn a train control system, an electropneumatic valve, a circuit normally maintaining said valve closed to prevent a brake application, an electrical device energized by an impulse transmitted to it from a source exterior to the vehicle to open said circuit, means for delaying the brake application taking place for a predetermined period of time, after the circuit is opened, and a manually operable acknowledging lever operated to cause the reclosure of said circuit before the expiration of said predetermined period of time and operable to cause the closure of said circuit after the predetermined period has expired only if the train has come to a complete stop.

9. In a train control system applied to a railway system having its trackway divided into blocks, a pair of cab carried signals, a magnet for actuating said signals at the exit of a block when the traffic conditions ahead are unfavorable, manually controlled means operable to retire only one oi said signals, and means for temporarily preventing the retiring of said one signal after the expiration of a denite interval of time following the first change.

10. In a train control system, a vehicle carried relay, trackway means for inductively transmitting impulses to said relay to cause it to operate, an electroinagnet included in a circuit controlled by said relay, visual and audible signals actuated by said electromagnet when the train is about to enter caution territory, manually operable cknowledging means for energizing said magnet to stop the actuation of said audible signal, and means operable only when. the territory about to be entered is clear for retiring the visual signal.

11. In a train control system, vehicle carried visual and audible signals together with apparatus for controlling the brakes of the vehicle, pairs of trackway magnets spaced at points along the trackway for transmitting controlling iniiuences from the trackway to the vehicle, a relay carried by the vehicle responsive to said iniluences to variably change the condition of said signals and to initiate the operation of said brake controlling apparatus and manually controlled means operative to iniluence said relay and apparatus to change the condition of only one oi said signals and for preventing a brake application occurring under certain conditions.

l2. In a train control system, an inductive pickup relay, means or securing said relay to a vehicle, a brake valve control circuit passing through contacts of said relay normally and held closed to prevent a brake application, and means included in said securing means for interrupting said circuit in case the relay is moved any appreciable distance with respect to the securing means.

1S. In a train control system, an impulse receiving device suspended from vehicle in a denite relation thereto, and circuit for said device including a brittle conductor extending between said receiving device and the vehicle which will be severed if relative movement between the vehicle and receiving device occurs.

14. In a train control system the intermittent inductive type, cab signals, associated means for causing one of said signals to be elective when the vehicle is in clear territory and for automatically causing another of said signals to be effective upon the vehicle entering caution territory, means for initiating an automatic brake application coincident with the actuation of the last mentioned signal, a manually controlled pneumatic contacter actuated to forestall the initiated brake application, and means ior maintain ig a third of said signals effective after the orestalling action has occurred..

l5. In a train control system, an electropneumatic valve, a normally closed operating Acircuit for said valve, a train carried relay having contacts through which said circuit passes, trackway elements for operating said relay to cause the same to open and close said circuit, means for immediately warning an engineman when the circuit is broken, means for further warning the engineman, manually operable means whereby the engineman, ii alert, can cause the relay to again close said circuit, brake applying means effective if the engineman fails to operate said manually operable means, and means for preventing the engineman from effecting said circuit closure alter the bra-kes have been applied until the train has come to an absolute stop.

16. In a train control system, a pair of pneumatically operable contacts, means operable during the progress of a vehicle ior only at times causing a momentary actuation of said contacts, and other pneumatically operative contacts under the control of said rst means permitting a closure of said last contacts only after the vehicle has been brought to a standstill.

17. In a train stop system, a set or" pneumatically actuated contacts, a second set of contacts, a control circuit including said contacts sets and Linder control of said second contact set while the rst set is in actuated position, and a third set of contacts included in a branch of said control circuit under control of said second set when the rst contact set is not actuated.

18. In a train control system, means responsive to trackway conditions to be changed from normal to operated position, brake applying means initiated upon operation of said responsive means, and a plurality oi separate, manually controllable, pneumatic reset means foreach moving the responsive means from its operated, to its normal position.

19. In a train control system, car-carried apparatus, including a single means responsive to trackway conditions, train control means controlled by said responsive means, and a plurality of manually controlled pneumatic reset means for restoring the responsive means after its operation in accordance with trackway conditions.

2G. In a train control system, car-carried apparatus, including, a pair of pole-pieces having an armature associated therewith, movable from one of its pole-pieces responsive to trackway conditions, train-control means controlled by said armature; reset means, separate from that employed to iniiuence said pole-pieces responsive to trackway conditions, for restoring said armature; and a plurality oi separate manually controlled means for causing said reset means to function.

21. In a train control system, brake applying means, a normally inactive member operable in accordance with traffic conditions to cause initiation or" said brake applying means, a restoring member arranged to be physically moved by iluid pressure, a fluid pressure timing reservoir, and a manually operable member operable to cause fluid pressure in the reservoir to communicate with, and thereby move, the restoring member to a position to cause said normally inactive member to resume its inactive condition.

22. In a train control apparatus, the combination with a magnet valve device operative to cause an automatic application of the brakes, of electro-pneumatic means operative to control the operation of said magnet valve device for governing the release oi the brakes, and means cooperating wit'n said electro-pneumatic means and adapted to time operation of said electro-pneumatic means.

23. In a train control system of the intermittent inductive type applied to a railway system wherein the trackway is dividedup into blocks, a pair of cab carried signals, means effective at the exit of each block for causing both signals or said pair to be actuated under certain traflic conditions ahead, manually controlled means for causing the operation of one signal of said pair to cease, and means influenced by said manually controlled means for causing the operation of the other signal of said pair to continue While the train proceeds through the major portion of the next block.

24. In a train control system, a normally energized electro-pneumatic valve for normally preventing an automatic brake application occurring, means for causing the magnet of such valve to become deenergized, means for delaying a brake application occurring for a definite interval after the deenergization of such magnet occurs, and a cab carried readily accessible manually operable element having pneumatic equipment controlled thereby to bring about the reenergization of the magnet of said valve only if operated before said predetermined interval has expired, or after the vehicle has been brought to a standstill. Y

ALFRED E. HUDD.

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