US1703844A - Train control - Google Patents

Description

Feb. 26, 1929.

W. D. HAILES TRAIN CONTROL Filed Nov. 26, 1924 z ATTORNEY Patented Feb. 26, 1929.

UNITED STATES PATENT OFFICE.

WILLIAM D. HAILES, OF ROCHESTER, YORK, .A SSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK.

TRAIN CONTROL.

Application filed November-'26, 1924. Serial m. "2,337.

This invention relates to a reversing switch for automatic train control systems.

In train control practice, the progress of the train is usually governed in accordance with control influences communicated from the trackway to suitable receiving devices located on the vehicle. In order that the vehicle may proceed with either endleading, it becomes necessary to change or reverse the connections between these receiving means and the car-carried control means.

It is essential that the switch device employed for making this change of connections be of rugged mechanical construction, that its contacts be heavily insulated, and that the switching mechanism as a whole be protected from moisture, dust, cinders and other foreign matter. In order to provide a switch of this character, it is desirable to use a manually operable switch which can be of a suitably heavy mechanical construction, and can be located in the cab of the vehicle in a position to be adequately protected from moisture or other foreign matter.

It is an object of this invention to provide a reversing switch for automatic train control systems which will be manually 0per able, at least as to the majorityof its contacts, and which may belocated at a pro tected point on the vehicle.

In applying train control systems to exist ent railway systems, it is found that certain sect-ions of trackway are'equipped for auto-' matic train control, while certain other sections are not so equipped. For this reason, means are provided by which, undergiven control conditions, the car-carried control apparatus may be set to an inactive condition 7 and so maintained until an influence is again received from the trackway. As one set of receiving 'means only can receive energy when the vehicle is proceeding in a given direction, it is apparent that if a manually operable. reversing switch alone were employed, the engineer or train operatorcould, by manipulation of such switch, prevent the carcarried control apparatus from responding upon the return into territory equipped.

for automatic train control.

'It is another object of this invention to provide means to prevent the operation of a train equipped with a manual reversing 7 having been shown.

tinctive exponents.

to allow such movement to be made without a manual switch operation are made at a low speed.

It is a further object of this invention to provldemeans for permitting a train to proprovided they ceed against the normal direction of traflic 'without a manual switch operation, provided such a move is made below a minimum speed limit.

Other objects and advantages of this invention will be pointed out or will become apparent as the description progresses.

In the'drawings, a section of trackway equipped for automatic train control, together with the car-carried apparatus embodying the present invention, have been shown in a simplified and diagrammatic manner. Referring particularly to the trackway, the-rails 1 are dividedinto blocks by the insulating joints 2, the block I and the adjacent ends of two other blocks H and J The normal direction of'train travel along 'the trackway isindicated by the arrow.

As the circuits and apparatus used in the. several blocks are substantially identical, :1

description of these circuits and devices'in v one block only will be given, corresponding elements in the adjacent blocks being identified by like reference characters having dis Any suitable type of trackway may be used with this invention, and the simplified embodiment shown is a so. called two-position single phase system. Referring to the trackway circuits, track signal and train control currents are imposed across the rails at the exit end of each block b means of the track battery 3 and the secon circuits ary winding of the transformer 4 as shown.

The primary winding of the transformer l is energized through the contactfingers 5 and 6 of the track relay 7 and the transformer 8 which is connected across the transmission line 9 as clearly shown in the drawings.

, Wayside signals of the semaphore, light signal or any other suitable type are pref-f erably. used in connection with the track circuits. For the purpose" of illustration, semaphore signals Z of the type common in railway signaling practice, have been con ventionally shown at the entrance end of each block; The means for operating these semaphore'signals from the track relays 7 V have not been shown, as these means are unmay be of anysuitable construction, but is derstood by those skilled in theart, and as these means form no part of the presentinvention.

e A railway vehicle has been conventionally represented in the block Iby the wheels and axles 10 and 11. In front of the leading axles l0 and behind the trailing axles; 11,

over and in inductive'relation to the track rails, are mounted two pairs of receiving coils 12 and 13 as shown. The windings of each pair of receiving coils are so connected that currents induced in the coils of each pair by currents. flowing in opposite directions in the two track rails will be additive. .These receiving coils may or may not be mounted on laminated iron cores.

7 The coils 12 are active, to secure proper control, when movement is in the normal di rection of travel, with the pilot first, and coils 18 are so active when movement is in the normal direction of travel (that of the arrow) with the tender first.

The 1 connections between coi-lsjand the other car carried control apparatus are made through a manually 0perable reversing switch RS. This switch preferably well insulated and provided with large contacts, and is so mounted as to be protected from moisture,.dust, cinders, or

other foreign matter. In the simplified form shown, the reversing switch consists of a bar it on which are pivotallymounted 1 three movable contact fingers 15, '16 and 17,

insulated from the bar l gand an operating handle 18. The stationary contacts 19, 20, 21, 22, 23 and 2% are provided, and are arranged m SUCll'POSllQlOIlS as to be en; ;a{ {ed by the movable fingers 15,16 and 17 when these .fingers are in their extreme positions as shown. Themovable fingers 15, 16 and 17'a'nd the operating handle'18 are pivoted atone end so that the fingers may be swung from one position to the other-by means of the operating handle.

An amplifier is provided, and is conventionally represented in the drawings at A.

This amplifier is preferably of the type the receiving 7 which acts to respond to weak current impulses in its input circuit and to produce more powerful current-s in its output circuit, and maybe of the vacuum tube type.

.A shaft 25 is geared or otherwise suitably driven from an axle of thevehicle, the connection between the shaft- 25'and the axle being represented by a dot and dash line. ,This shaft 25 carries a gear wheel 26 which perates an automatic reversing .switch or check switch. This check switch consists of a toothedsector divided by the insulating section 28 pivoted at the point 29 and carrying a resilient contact arm 30.

Two stationary contacts 31 and 32 are prov1ded to cooperate with the contact arm in its two extreme posit-ions. It isobvious.

that when the shaft 25 is rotated one direction, corresponding to a given. direction of vehicle travehthe sector 27 is thrown to one of its extreme positions and the contact arm 30 is brought intofirm' contact vwithone of the stationary contacts, say 31,

and is held in that position until the-vehicle reverses its direction oftravel,.ywhen the sector 27 will immediately be thrown to its other extreme position, causing the contact arm 30 to engage the stationary contact 32.

A centrifugal speed responsive deviceor centrifuge G is also mounted 'on the shaft 25. This centrifuge has been represented in a simphfiedform for the sake of clarity, it

being understood that anyform of centrifuge adapted to this type of system might be employed. The centrifuge illustrated consists of a collar 33 rigidly fastened to the shaft 25, and a collar 3% which is movable on this shaft, these collars being connected by thelinks 35-36 carrying the weights 37, and being urged apartby. the spring 38. The movable collar 34 engages a lever 39 which is pivoted at the point 40 and the free end of which forms a contact arm l2.

It is apparent that as the speedof the veiicle ncreases, the-weights 37 will be thrown outwardly,drawing the-collar 3 f downward against the resistanceofthe spring 38, and

thus causing the contact arm 42 to move over its associated speed contact segments 4:33Ild44u.-

A main car relay 'MR and a non-control lay NC is preferably of the slow acting type, that is, its parts are so constructed and arranged that it will not open its contacts immediately on the de-energization of its windings. This may be accomplished by 'be effected by manual actuation. As the specific type of the electro-pneumatic valve is used is lmmaterlal, a conventional form of valve has been shown, it being understood that any other suitable type of electro-pneumatic valve or brake control might be used without departing spirit of the invention.

A push button PB is provided for picking up the non-control relay NC. This push button is located at some convenient point in the cab of the vehicle within reach of the engineer. This push button PB is enclosed in a box or housing, which is preferably apparatus from the sealed or locked, the key being in the possession of a tower man or other oflicial located at a point where thetrain passes from trackway territory which is equipped for automatic train control to trackway territory not so equipped.

Operation.-In the drawings, all of the contacts and devices have been shown in their normal operating positions, that is, the positions which would be assumed with the train running at speed and in the normal direction of traffic, over a section of trackway equipped for automatic train control in which clear tralfic conditions exist and with the reversing switch set in its proper position.

Assuming that a train is proceeding along the trackway under clear trafiic conditions,

that is, with no train in the block in which the train is located or 'in the next block in advance, the leading receiving coils 12 will have currents indicated therein by the train control current flowing in opposite directions in the track rails. These currents will. be

impressed on the input circuit of the amplifier A through a circuit which may be traced as follows :from the receiving coils 12, wire 45, stationary contact 22 and movable finger 16' of the reversing switch, wire 46, the input circuit of amplifier A, wire 47 movable finger and stationary contact-"20 or" the reversing switch, wire 48 to thereceiving coils 12.- This receiving circuit is resonated to the frequency ofthe' train con 'traced as terminal B, through contact arm 42 and Seg- Iment 43,:iwires 58and 57 and I the winding trol current by means ofrthe condenser M connected across the in ut circuit of the amplifier A, as shown. T e main car-relay MB is energized from the output circuit of the amplifier A through wires'49 and 50. The energization of the main car relay MR causes its contact finger 51 to be attracted, closing its front contact and so maintaining an energizing circuit for the electropneumatic valveEPV which may be traced as follows:beginning at the battery terminal B, through contact arm 42 of the speed arm 39, contact segment 44, wire 52, contact finger 51 and front contact of the main relay MR, wires 53 and 54, contact arm and stationary contact 31 of the check switch, wire 55, stationary contact 24 and -movable finger 17 of the reversing switch,

wires 56 and 57 and the winding of the electro-pneumatic valve EPV to the battery terminal C. For the sake of simplifying the drawings, the letters B and C have beenused to represent the opposite. poles of a source of electrical energy which may be the opposite terminals of a battery.

\Vith the electro-pneumatic valve EPV energized, the train may proceed at speed in the clear block. If the train speed'exceeds a maximum limit of, say 60 miles per hour, the contact arm 42 will be moved by the centrifuge G until it no longer makes contact with-the segment 44, thus breaking the circuit to the electro-pneumatic valve EPV, traced above, and causing an automatic brake application. This brake application continues until the train speed has been brought below the maximum limit, assumed to be 60 miles per hour, when the contact arm 42 again engages the segment 44 and the electro-pneumatic valve 'EPV is again energized, to permit releasing the train from the automaticbrake application.

Now assume that a train equipped for automatic train control of the type embodying this inventiom'while running at speed under clearjtraflic conditions, enters a block in which cautijontrafiic conditions exist, that is, a block in which the train control cur- Hence, the receiving coils 12 fail to pick up current and the main relay MR is therefore de-energized, breaking the circuit to the 'electro-pneumatic valve EPV traced above andcausing an automatic brake application. This brake application continues until the train speed has been reduced to a certain minimum value assumed to be 15 miles per hour, when the contact arm 42 engagesthe segment 43,'clos-ingan energizing circuit to the electro-pneumatic valve which may be follows :-from the battery of the electro-pneumaticvalve EPV to the battery terminal -C. The brakes may now be released and the train proceed below the minimum speed limit, until traflic' conditions ahead become more favorable.

When atrain enters a danger block, that is, a block in which another train 1s located,

or in which other dangerous conditions of trackway exist, the train control current remains cut ofi from the track rails, and the train may proceed only at a speed below the .minimum speed limit in a manner described in connection with a train in a caution block. Now assume that the train comes to a point. on the trackway at which a change from train control territory to territory not equipped for train control is to be made.

lVith the particular simplified type of noncontrolapparatus shown in this embodiment of the present invention, the engineer will bring the train to a stop at the beginning of the unequipped territory andthe tower man ;or other official at this point will unlock the push button housing and depress .the push button PB. Since the train is I1OW:11'1 un equipped territory and no traincontrol currentis flowing in the track rails, the main relayMR .is de-energized, and its back contact 59 is closed. The depression of the push button PB therefore energizes thenon-control relay NC through a circuit which is f obvious. from the drawings, this relay being wire 63 andthe winding of the non-control relay NC to the battery terminal C; The non-control relay NC being energized, attracts its contact finger 64L, closing-the front contact of' thisj finger'and completing an energizing circuit for the electro-pneumatic valve- EPV, which circuit may be traced as ,followsa from the battery terminal B,

through contact finger 64;. and front contact of the non-control relay NC, wires and 54,

contact arm 30 and stationary contact 31 of the check switch, wire 55,}stationary contact 24. and contact. finger 17 of the manual reversing switch, wires 56 and 57 and the winding oi the electro-pneumatic valve EPV to the battery terminal C.

v The electro-pneumatic valve EPVis now energized and the train may proceed without further restriction in, the unequipped territory. lVhen'the train again reaches a section of trackway which is equipped for autoinane train control, the receiving coils '12 (again have currents induced therein by the current flowing in the track railsand the 'll'litln relay MR 1s again energized, attracting its contact fingers 51' and 59. The attracting of contact finger 59 breaks itsback contact and'so opens the stick circuit to the non-control relay NC, causing this relay to retract its contact fingers 62 and 6e. As the ,front contactlof finger 51 of the mainrelay trackway regardless of whether the first block encountered is in the clear or the cautlon condition, a short permanently energized section of trackway may be provided at the point where the return to train control territory is made. Tlns energized sectlon' will always act to energize the main relay MR and so to drop the non-control relay NC, thus placing the car-carried control apparatus in its active condition.

In the practical application of automatic train control systems, it is found that in traclrway territory unequipped for auto matic train control, stray currents or transients,asthey are called, fiow'in the'tr'ack rails for .short distances. These currents may becaused by'the leakage'of track circuit signal currents from adjacent track rails, or they may arise from any other source. It is obvious that if a trainequipped with the system embodying the present-invention encounters these stray currents while operating in-unequipped territory, the main car relay MR would be re-energized, causing the non-control rela y NC to retract its contact'fingers, so placing the train under the control of the automatic apparatus, and causing an automatic brake application bringing the'train to a stop after said stray currents ceased to' be efi ect-ive- In .order to avoid the delay and inconvenience imposed by such actionof strayjcurrents or transients, the non-control relay NC is made slow' acting, as hereinbefore pointed out. This slow acting feature enables the noncontrol relay NC to maintain its contact fingers'62 and 64 attracted for a period of time arranged to correspond-to the time required for train travel" over the longest stray current section ordinarily encountered in practice. j

Now assume that a train is proceeding in unequipped territory with its car-carried control apparatus in the inact ve condition,

that is, with the non-control relay NC stuck up and the electro-pneumatic valve EPV energized, and also assume that the engineer or train operator endeavors to avoid the reconditionl'upon tlie-returnof the train to equipped territory by merely reversing the connect-ions to the receiving coils (without 'settingof the control apparatusto its active at the same time reversing the direction of travel of the engine) and so connecting the input circuit of the main car relay MR to the trailing receiving coils 13, whiclrcannot receive train control current in any substantial or operative qua-ntitydurlng travel in the direction of the arrow. This change of the manual reversing switch places the movable finger17 in engagement with the stationary contact and thus breaks the circuit from the non-control relay NC to the electro-pneumatic valve EPV, causing an immediate automatic brake application. This brake application continues until the train speed has been brought down to the minimum speed limit, assumed to be 15 miles per hour, at which speed the contact arm 42 engages the 15 mile per hour segment 43, and the electro-pneumatic valve is re-energized through a circuit which has been traced.

above. The train may now proceed, but only at the restricted speed of 15 miles per hour, until the manually operable reversing switch is properly set, when the main car relay MR will again be connected up to the active receiving coils and again be energized it coils 12 are receiving current. v The reenergization of the main relay MR causes It to attract its contact finger 59, thereby opening the stick circuit to the non-control relay N C and placing the vehicle under the control of the main relay MR. 1

Now assume that a vehicle equipped for automatic train control of the type embodying this invention leaves the roundhouse, siding or other non-control point and enters an equipped section of trackway. If the manually operable reversing switch is properly set to correspond with the direction of travel of the vehicle, the receiving coils immediately receive energy from the trackway, and the vehicle may proceed at speed until a block in which caution traffic conditions exist is encountered. If, however, the manually operable reversing switch is not properly set, that is, is set in the ositlon corresponding to train travel in t e reverse direction from that in which the vehicle is proceeding, the circuit through the main relay MR to the electro-pneumatic Valve EPV is broken at the contact finger 17 of the reversing switch, and the brakes are applied until the train speed has been reduced below the minimum speed limit assumed to be 15 miles per hour, at which speed the contact arm 12 engages the speed segment a3, energizing the electro-pneumatic valve EPV through a circuit which has been traced above. The vehicle may now proceed at the minimum speed until the manually operable reversing switch is properly set.

In railway practice it is sometimes necessary to make short moves, usually at a low speed and for varying distances, against the normal direction of traflic, as in taking the slack out of a train, in backing into a siding or for any other reason. It is desirable that such back-up moves should be permitted without the delay or inconvenience imposed by a manual actuation of the reversing switch. Since the length of such back up move is indeterminate, it is not thought desirable to limit the train operator or engineer as to the distance of travel of such moves, but as a train running in a direction against the normal direction of traffic is a. hazard to following trains, it is thought desirable to limit the speed at which such back-up move may be made. This invention provides that such back-up movement, in equipped territory only, can be made without necessity for operation of the reversing switch RS provided the speed be kept within a low speed limit.

Assume now that a train, stopped in territory equipped for automatic train control, makes a. short back-up move, the manually operable reversing switch remaining in its forward running position. The sector 27 is thrown into its reversed running position by the gear wheel 26 causing the contact member 30 to disengage the stationary contact 31 and to engage the stationary contact. 32. This breaks the circuit to the electro-pneumatic valve EPV through the main car relay MR, but the electroneumatic valve EPV remains energized t mile per hour speed segment 43, so long as the train speed does not exceed the assumed minimum limit of 15 miles per hour. Thus back-up moves in equipped territory may be made without the operation of the man ually operable reversing switch, provided the minimum speed limit is not exceeded. Also, if such back up movement in equipped territory beaccompanied by operation of reversing switch RS, the speed is still'restricted to the low speed limit, since under these conditions, relay MR is down and EPV can be energized only through low speed contact 43.

If, in equipped territory, the engineer attempt to defeat this system, by simultaneously reversing switch RS and the direction of travel of the train, MR being down due to being deprived of current from the rough a circuit including the 15- V receiving coils 13, the speed of the train is limited by the low speed'contact 43.

On the other hand, whilelnot at all probable, should the switch RS be reversed and the direction of train movement also reversed, in unequipped territory, relay NC already being up, EPV would be energized through a circuit including finger 64 and front point of NC and fingers 3O andvl-7 of the automatic and manually operated switches respectively, so that the train speed would not be restricted to the low speed limit, by low speed contact 43. This been shown "and described has been disclosed for the purpose of explaining the nature of'the invention rather than for the purpose of limiting its scope. It should however is not I particularly undesirable wholly within control of the engineer so that he is not restricted in his operation ofthe train and knows that the full responsibility rests on him.

Itis'to be understoodthat the specific embodiment of this invention which has be further understood that many additions, modifications and combinations could be made without departing from the spirit of the present invention. For instance, a polyphase car relay might be-used, imposing different speed'restrictions in caution and danger blocks, the setting up of the non-control relay might be accomplished by means of special trackway apparatus located at the point of the beginning of non-control territory, or many other changes, additions or modifications might be made.

What it isdesired to secure by Letters Patent is 1. In an automatic train control system, car-carried control apparatus for controlling the-brakes of a vehicle, two sets of re ceivingf means for inductively receiving influences from the trackway, a manually operable reversing switch associated with said sets of receiving means, an automatic check switch controlled by the direction of travel of the "vehicle and associated withsaid brake controlling apparatus and said manually operable reversing switch, and

means for imposing a restrictive speed limiton thevehicle if said manually operable reversing switch is set for a direction ofvehicle travel opposite to that in which the direction of travel of the vehicle, said the vehicle is proceeding.

2. In an automatic train control system, car-carried apparatus comprising, a brake control device, a main relay, a manually operable reversing switch having two operating' positions for controlling a circuit to said' main'relay, a speed-responsive control device and an automatic check switch acting while the trainis traveling in a given direction to control said brake control device by said main relay when saidmanually op-' vof the type in which control influences cor responding to traflic conditions are inductively transmitted from the traclrway' to a' 'moving vehicle, car-carried apparatus including two seats of receiving means, a

two-position manually operable reversing switch, a brake control device, a speed governed control means associated with said brake control device for imposing a high or a low speed restriction and a checkswitch operated by the direction of travel of the vehicle and electrically associated with said manually operable reversing switch,-,said check switch acting while the train is traveling in a given direction to impose said low speed limit ifthe manually operable reversing switch is in one position and to impose saidhigh speed limit if the manually operable reversing switch is in the otherp'osition.

4. In an automatic train control system of the type in which control influences corresponding to traffic conditions are inductively received from the trackway, car-carried brake control apparatus comprising two sets of influence receiving devices, one of said sets receiving said influences when the vehicle is proceedingwith one end leading and the other of said sets receivingsaid influences when the vehicle is proceeding with the other end leading, a main relay, a manually operable reversing switch for connecting said main relay alternately to each of said sets of receiving'devices, a check switch operated by the direction of travel of the vehicle, and a brake applying device, said main relaycontrolling said brakeapplying device through a circuit including'a contact of said check switch and a contact of said manually operable reversing switch.

5. In anautomat-ic train control systemot the typein which control influences correspondent to traflic conditions are inductively transmitted from the trackway to a moving vehicle, car-carried apparatus including two sets of influence receiving devices, a m'anually operable reversing switch, a brake control device, and a; check switch operated-by check switch being electrically associated with said manually operable reversing switch" and cooperating therewith to render said brake control'device active'ifsaidmanually'operable circuit controller is not in a. position to correspond with the direction of travel of the vehicle;

6. In an automatic train control system, vehicle-carried control apparatus compris-' ing two sets ofreceiving devices, a main re lay, a two-position manually operable reeach of said sets of receiving deviceswith said main relay, a check switch operated by the direction of travel of the-vehicle, a brake control device, a speed'governed switch having a contact opened at a. high speed and a contact opened at a low speed, and a control circuit for said brake controlling means, controlled jointly by said" hi hspeed contact of said speed governed switch and a versing switch for alternatively connecting position for a l l I contact of said main relay when said manually operable reversing switch is in one position, and by said low speed contact of said speed governed switch when said manually operable reversing switch is in its other given direction of vehicle travel. 7

7. In an automatic train control system of the type in which control influences corresponding to traflic conditions are inductively transmit-ted from the trackway to a moving vehicle, car-carried apparatus comprising two sets of receiving devices, means for controlling the brakes of a vehicle, a twoposition manually operable reversing switch having an auxiliary contact controlled by the direction of travel of the vehicle, and means including said manually operable reversing switch for operating. said brake control means in accordance with said control influences when said manually operable reversing switch is in one position and for imposing a low speed restriction when said manually operable reversing switch is in its other position for a given direction of vehicle travel.

8. In an automatic train control system, vehicle-carried apparatus comprising, means for inductively receiving control influences from the trackway, means for controlling the brakes of the vehicle in accordance with Such influences, and a reversing switch for connecting said receiving means to said brake controlling means including a manually operable contact finger and a contact operated by the direction of travel of the vehicle, said contacts cooperating to close a circuit to said controlling means only when said manually operable contact is in a position corresponding to the direction of travel of the vehicle.

9. In an automatic train two sets of receiving devices for receiving control influences from the trackway, a man ually operable reversing switch associated with said receiving devices, an automatic check switch controlled by the direction of travel of the vehicle, and means for imposing a restrictive control upon the vehicle if said manually operable reversing switch and said automatic check switch are not in corresponding positions.

' 10. In an automatic train control system for railroads, the combination of influence transmitting means partly on the vehicle and partly along the trackway for transmitting control influences from the trackway to the vehicle, speed restricting apparatus governed in accordance with traffic conditions ahead through the medium of said influence transmitting means, said apparatus including a brake setting appliance which applies the brakes of the train if the speed of the train is excessive, and means governed in accordance with the direction control system,

of movement of the vehicle for restricting the speed of the vehicle to below a low' limit if the vehicle-is moved backwards regardless of the then existing traflic conditions.

11. In an automatic train control system of the continuous inductive type, the combination of influence receiving elements located over the trackway in front of the first axle of the train adapted to have voltages induced therein inresponse to alternating train control current flowing down one track rail through the axles of the train and back through the other rail, speed control mechanism including a brake setting appliance which permits the train to travel at a high speed without incurring a brake application while the train is moving forward and train control current is flowing in said track rails, and means for causing said speed control mechanism to permit the train to proceed only within a low speed limit effective if the direction of movement of the train is reversed at a point where train control current is flowing in said track rails.

12. An automatic train control system of the continuous inductive type comprising, a normally energized brake setting appliance, means including a speed responsive device for maintaining said brake setting appliance energized in response to the flow of train control current flowing down one track rail through the wheels and axles of the train and back through the other rail and which restricts the train to a low speed limit if the flow of train control current in the track rails is cut off, and means governed in accordance with the direction of movement of the train effective to permit the train to proceed only within a low speed, limit if the direction of movement of the train is reversed in territory where train conltrol current is flowing in said track ra1 s.

13. An automatic train control system comprising, a normally energized brake setting appliance, influence communicating means for transmitting control influences from the trackway to the vehicle in accordance with traffic conditions ahead, speed control mechanism setting up a high speed limit under favorable traffic conditions and setting u a low speed limit under unfavorable tra 0 conditions ahead which efl'ects de-energization of said brakesetting appliance and effects a brake application if the speed limit is exceeded, and means governed in accordance with the direction of movement of the train effective to restrict the train to travel within a low speed limit if the direction of movement of the train is reversed regardless of the then existing traflic conditions.

14. In an automatic train control system, two sets of receiving devices for receiving control influences from the trackway, a manually' operable reversing switch associated withsaid receiving devices, and automatic switch means governed in accordance with the direction of travelfor pi'eventing nis use of the said reversing switch.

15. In an automatic train control system, two sets of receiving devices for receiving control influences from the trackway, a manually operable reversing lever associated With "said receiving devices and an automatically operated switch governed by the direction of vehicle travel for imposing a penalty if the reversing switchand the direetion of travel of the vehicle are not in correspondence. 7

In testimony whereof I afiix my signature.

WILLIAM' D. HAILES. V

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