US1824174A - Train control - Google Patents

Description

Sept. 22, 1931.' w. H. REICHARD TRAIN CONTROL Filed Aug. 18, 1924 wu siwuj 3 in :11 3% FNZR. Aria/away 1 Patented Sept. 22, 1931 UNITED STATES PATENT OFFICE ADE H. R'EICHARD; OF ROCHESTER, NEW YORK; ASSIGNOR Tp GENERAL SIGNAL COMPANY, OF ROCHESTER, N EW YORK RAILWAY TRAIN CONTROL Application filed August 18, 1924. Serial No. 732,753.

This invention relates to train control systems, and more particularly to systems of the two position continuous inductive automatic stop type as distinguished from a speed'control system.

In the common type of train. control systems, control influences corresponding to traffic conditions ahead are inductively communicat'ed from the tracltway to a moving vehicl' These control influences may be set up by means'of currents flowing in the track rails, in wave w-ires, or in other suitable conductors along the trackway, and usually two alternating currents with a phase displacement therebetween are set up, one flowing in opposite directions in the two track rails or other conductors, and the other flowing in the same direction in the rails or conductors. In a: train control system ofthe typeernbodying this invention, when a train or vehicle enters a caution block, that is, a block in the rear of a block in which another train is located, a switch is opened, a rail broken or other dangerous condition exists, one of the above mentioned influence transmitting or control currents is cut off-from the track rails or other conductor, and the car-carried apparatus on the following trainis so affected by this lack of current that it brings the train to a stop after which the engineer may set the brake control apparatus to an inactive condition by operating a manual switch accessible only from the ground. In order that there may be a change in the car-carried control apparatus in each caution block to enforce a stop or other restriction, it is desirable toprovide an auxiliary circuit which will act to reset the car-carried control apparatus to its active condition atthe end of a caution block. Since the'control of'the automatic stop in a danger'block isdependent upon: the resetting of the-control apparatus by the auxiliary circuit, it is important that this circuit should always-carrycurrent. and in accordance with this invention, it is proposed to provide means for checking the integrity of this circuit and indicating-when it is out of order.

Other objects'and advantages of this invention will'be pointed out or will become ap parent as the description of the system as a whole progresses.

In the drawings a section of trackway equipped for an automatic stop system of the type embodying this invention including the trackway' apparatus for making a change to non-coi'itrol' territory, together with carcarried brake controlling apparatus has been shown in a diagrammatic and simplified manner.

Referring particularly to the trackway circuits in the territory which is equipped for automatic train control, the track rails 1 are divided into blocks by the insulating joints 2, the blocks I and J, and the adjacent ends of the blocks H and K having been shown. As the trackway circuits and apparatus in the adjacent blocks in equipped territory such as blocks H and are substantially identical, a detailed description of such circuits and apparatus in one block only will be given, corresponding elements in the adjacent blocks being referred to with like reference characters having distinctive exponents.

An alternating current is impressed upon the track rails l by means of the transformer 3, the primary winding of which is energized from the transmission line 25. This current flows in series through the two track rails through a circuit which may be traced as follows :From the secondary of the transformer 3, through wire 4, adjustable impedance 5, wire 6, track rail 1, relay 8, track rail 1, wire 10 to the secondary of the transformer '3. This current, which flows in series in the two track rails, will hereinafter be referred to as the loop phase or track phase current. A second current is impressed on the two track rails in multiple through a circuit which may be traced as follows :F rom a source of energy comprising the secondary 11 of the current transformer 12, through wire 13, contact finger 14 of track relay 8 wires 15'and 16,.balance impedance 17 Lhe two track rails 1 in multiple, balance impedance 18', and wire 19 to the secondary 11 of the current transformer 12. This second current, flowing in the two track rails in multiple will be hereinafter referred to as the line phase or simplex current. V

A constantly energized section of traclrway is provided at the exit end of each block.

he energizing circuit for this section is checked by reason of the fact that it also forms the source of current for the said line phase circuit traced above. This energizing circuit may be traced as follows :From the secondary of transformer 20, through wire 21, the primary winding 22 of current transformer 12, wire 23, balancing impedance 24 through the track rails 1 in multiple to balance impedance 17, and wire 16 to the secondary of the transformer 20. The primary windings of the transformers 3 and 20 are energized from the transmission line as clearly shown in the drawings. 4

It will be seen from the circuit to the permanently energized section of trackway, traced above, that energy is supplied to this constantly energized section from the transformer 20, and that the line phase current for the entire block is supplied from the same transformer 20 through the medium of the current transformer 12. V

A track relay 8 is connected across the track rails the entrance end of each block, as shown. This track relay may be of any suitable type, but in the presentembodiment is preferably of the alternating current type. It is evident from the circuits traced above and from the drawings that the presence of a train, a broken rail, an open switch or other dangerous traflic condition in the block I, would shunt the track ph ase current from the track rails, and cause the de-energization of the track relay 8. This would cause the track relay 8 to retract its contact finger 14, thus breaking the circuit to the line phase of the block H, as is evident from the drawings.

lVayside signals of the semaphore, light signal, or other suitable type, may or may not be used, as desired. For the purpose of illustration, wayside semaphore signals Z have been conventionally represented at the en trance end of each block. It is assumed that these signals may be operated from he track relays 8 in the usual manner, the means for providing such operation not having been saown, for the reason that such means are.

well known to those skilled in the art and form no part of the present invention.

The block J represents the last block in a section of trackway equipped for an automatic train control system of the type em bodying this invention. Track and line phase currents are impressed on the rails of this block in a somewhat different way than in blocks H and I, and as illustrated this is accomplished by the transformers 26 and 27, energized from the transmission line 25 as clearly shown. An excess energy section is provided at the end of the block J, that is, a section in which a higher intensity of line phase current is impressed in the track rails.

The energizing circuit for his excess energy section may be traced as. follows :Beginning at the secondary of the transformer :28, wire 29, balance impedance 30, the track rails 1 in multiple, balance impedance 31, and wire 32 to the secondary of the transformer 28. The primary winding of the transformer 28 is energized from the transmission line 25, as shown. In order that the control influences as represented by the track and line phase currents in the block J may reflect traffic conditions in the next block in advance, a track relay 33 is provided at the entrance end of the block K, which is assumed to be the first block in an unequipped section of trackway. This track relay 33 operates a movable contact finger 34 which acts to cut the line phase current in the block J when dangerous traflic conditions exist in the block K, as clearly shown in the drawings.

or reasons which will become apparent as the description of the system as a whole progresses, it is necessary that a phase displacement be maintained between the track and the line phase currents flowing in the track rails. In order to obtain this phase -relation, impedances or inductive reactances 5 are provided in the circuit for the track phase current in each block to produce lagging of the current in this circuit, whereas the resistances of the balancing impedance units 17 tends to avoid such lag in the line phase circuit.

A railway vehicle has been conventionally represented in the block H by the wheels and axles 35, its normal direction of travel being indicated by the arrow. In front of the leading axles of such vehicle, over and in in ductive relation to the track rails l, are located two receiving coils, 36 and 37. These coils may or may not have laminated iron cores. A similar pair of receiving coils is located behind the trailing axle of the vehicle, these coils being designated by the reference characters 38 and 39. The receiving coils 36 and 37 are so connected that potentials induced therein by track phase currents will be additive, whereas the receiving coils 38 and 39 are so connected that potentials induced therein by the line phase currents, flowing in the two track rails in multiple will be additive.

The receiving coils 36, 37. 38 and 39 are connected through the amplifiers A to the two phase windings 40 and 41 of a polyphase relay ME. The amplifiers A, which have been conventionally represented in the drawings, may be of any suitable type adapted to receive weak current impulses and to produce more powerful current impulses, and are preferably of the vacuum tube type. The input circuits of these amplifiers A are resonated by the condensers 42 and 43, connected across these input circuits as clearly shown in the drawings. A resistance unit 44; connected inthe input circuit of the amplifier A, connected to the winding 41, as shown in the drawings. This resistance 44 is normally shunted by the wires 1:) and 46 and the contact finger 47 of the control relay OR.

The main relay MR may be'of any suitable type adapted to train control practice. In the specific embodiment showu,this relay is of the polyphase type, having a movable element or rotor 48 which operates three contact fingers 49, 50 and Thisrelay, as well as are all the other relays included in the car- .carried apparatus, is preferably biased by springs or counter-weights so that it will assume a definite position upon the de-energination of its windings, and the moving element or rotor 48 is preferably mounted on a vertically arranged axis so as to be unaffected by the swaying or vibration of the train. I

A non-control push button NB is provided, this push button being preferably located in the cab of the vehicle, within access of the engineer or train operator. This noncontrol push button NB is provided with three movable contact fingers 52, 53 and 54. The contact fingers 52 and 53 close circuits immediately upon the depression of the push button. The contact finger 5e opensa normally closed circuit if the non-control push button NB is closed for more than, say, seconds. The retarded action of the contact finger 54 may be effected by any suitable means, and as shown adash-potD has been used for this purpose.

A reset push button BB is proviced in connection with the car-carried control apparatus, and is preferably located ata point on the vehicle which is accessible only from the ground, in order that the train must be brought to a stop before such reset push button. may be actuated. This reset push button RB may be provided with a counter or recorder, in order that the number of times that the engineer has used this device may be known to the ofiicial in charge of a particular section of trackway.

Cab signals H and NS are preferably provided in connection with the car-carried control apparatus. These cab signals may be of the light, semaphore or any other suitable type, and are located within view of the engin er or train operator.

An electro-pneumatic valve EPV 15 provided to control the brakes of the train. This electropneumatic valve may be of any type suited to train control purposes, and is preferably of the type which, when lo-energized, vents the brake pipe directly, or operates the regular engineers brake valve, so as to cause an automatic braxeapplication. This electro-pncumatic valve EPV is preferably so arranged and constructed that its actuation cannot be manually defeated.

The non-control relay NC is preferably of the slow acting type, that is, its parts are so arran ed and constructed that its contact fingerswill not be retracted'iinmediately upon the de-energization of its windings. This may be accomplished by providing a copper sleeve around the core to sustain the flux therein, orany other suitable means for producing a slow acting effect may be employed. The purpose of this slow acting feature will be apparent as the description of the system as a whole progresses.

he trackway and car-ca 'rie-o devices and circuits have been shown in their normal condition, that is to' say, the condition which they would assume under clear trafiic conditions ahead, and with substantially all circuits closed and energized.

Operaflour-Assume first, that a trainis proceeding under clear trafiic conditions ahead, that is with both traclr phase and line phase control currents fiowingin the track rails. The i ceiving coils 36 and 37 will induced therein by the track nts flowing in the track rails, iesemirrents will be amplified and imiressed on winding 40 of the main relay MR. .n a like manner, the receiving coils 38 and l have currents induced therein by the line phase currents flowing in the track plified and impressed on the winding 41 of the main relay MR. These currents'due to the track phase current and the line phase current flowing in the track rails will be out of phase as explained above. The main relay MR having both of its windings energized by currents which are displaced in phase will rotate its moving element 48, swinging its contact fingers--l9, and 51 to one extreme position. The contact finger: 50 closes a. circuit to the proceed cab signal H, which circuit may be traced as follows lrc-m the battery terminal B, through contact. finger 50, wire 55, contact finger 56 of the noircontrol relay NC, wire 57, proceed cab signal H, wires 58 and59 to the battery terminal C. The contact finger 51 of the main relay MR will close a circuit to the elec tro-pneumatic valve EPV, which may be traced as follows :F rom the battery terminal B, back contact and contact finger 54 of the non-control pushbutton NB, wire- 60, contact finger 61 of the reset push button RB, wires 62 and 63. contact finger 51 and stationary contact 66 of the main relay MR, wires 64- and 65 and winding-of the electropneurnatic valve EPV to the battery terminal C The electro-pneumatic valve EPV being energized through a circuit traced above, and a,

the proceedor clear cab signal H being displayed, the engineer or train operator may now proceed in the clear block without restriction as to speed.

In order to simplify the drawings, the lets and these induced currents will be a1nters B and C have been used to designate sources of electrical energy of opposite polarity, preferably the opposite terminals of a battery.

N ow assume that the train under consideration enters a block in which caution trat iic conditionsexist, that is, that the block in advance is occupied by another train or that some other dangerous tra'llic condition exists in such advancel block. The line phase current will be cut oil from the block under "onsideration a manner described above. and the car-carried receiving coils 38 and 89 will fail to have currents induced therein, and thus the winding 41 of the main relay MR will be Clo-energized. Since the energy is removed from the coil 41, he rotating elemerit B of the main relay MR will be moved to its ale-energized position by its springs or counter-weights Contact finger 51 will now disengage its stationary contact 66, breaking the circuit to the electro-pneumatic valve EPV, which circuit has been traced above. This will cause an immediate automatic brake application, bringing the train to a stop at some point in the block in advance oi the permanently energized section of trackway which is located at the exit end of the block.

The engineer may now dismount from the cab and depress the reset push button RB. This will cause the non-control relay NC to be energized through a circuit which may be traced as follows :From the battery terminal B, through contact finger 50 and stationary contact 67 oi the main relay MR, wires 68 and 69, contact finger '70 of the reset push button RB, wires 71, 72 and 7 3 and the winding of the non-control relay N C to the battery terminal C. Once-energized the noncontrol relay NC will be maintained energized through a stick circuit which may be traced as follows :From the battery terminal B, through contact finger 50 and stationary contact 67 of the main relay MR, wires 68 and 74:, contact finger 75 of the control relay CR, wire 76, contact finger 77 and front contact of the non-control relay NC, wires 7 8 and 73, and the winding of the noncontrol relay NC to the battery terminal C. The non-control relay NC being energized, its contact lingers 77, 56, C 9 and 80 are attracted. The contact finger 77 completes the stick circuit to the non-control relay N C as traced above. The attract-ion of the contactfingers and 79 de-energizes the cab signal H, and energizes or displays the non-control ca signal NS through circuits which are obvious from the drawings. The contact finger 80 closes an energizing circuit to the electropn-eumatic valve EPV which circuit may be traced as follows :-From the battery terminal C, through the winding of the electropneumatic valve EPV, wires and 81, front contact and contact finger S0 of the non-control relay N C, wires 82and 62, contact finger 61 of the reset push button RB, Wire GO, contact finger 54 and stationary contact of the non-control push button NB to the battery terminal B. It will be observed that this energizing circuit to the electro-pneumatic valve is closed only after the reset push button RE is released, closing its contact finger 61. This arrangement prevents the engineer or train operator from fastening the reset push button RB down and so avoiding the automatic stop restriction.

The electro-pneumatic valve EPV now being energized through the circuit traced above; the train may proceed without restriction until it comes to the permanently energized section of trackway near the exit end of the block. At this point, the receiving coils 38 and 39 will again have currents induced therein by the line phase current which is always present in this permanently energized section. The receiving coils 86 and 37 will also have currents induced therein as described above, and the windings 4:0 and 41 of the main car relay MR will both be energized, causing the moving element l8 or" this reiiy to revolve to its energized position.

he contact finger 50 will move away from the stationary contact 67, breaking the stick circuit to the non-control relay NC traced above, and causing this non-control relay to retract its contact fingers 77, 56, 79 and 80. The retracting of contact finger 56, together with the swinging of contact finger 50 of the I main relay MB to its extreme energized position, will cause the energization of the proceed cab signal H through a circuit which has been traced. The retracting of the contact finger 79 of the non-control relay NC will cause the de-energization of the noncontrol cab signal NS as clearly shown. The retracting of contact finger 80 of the non-control relay NC breaks the energizing circuit to the electro-pneumatic valve EPV, but the electro-pneumatic valve is maintained energized through a circuit including the contact linger 51 of the main car relay MR, which circuit has been traced above.

From the above description it is clear that the car-carried control apparatus is now in its normal condition and the train may proceed into the next block with automatic restriction depending on traffic conditions ahead.

Should the engineer attempt to forestall the resetting of the car-carried control apparatus to its normal condition by depressing of the non-control push button N13 for the purpose of breaking the shunt around resistance 4-4 at the point of train travel where the permanently energized section of trackway was encountered, the control relay CR would be energized through a circuit including the contact linger 52 of the non-control push button NB which circuit is obvious from the drawings. The energization of the control relay CR would attract 1ts contact finger 75 breaking the SlLlCk'CllCllli? to the non-control ,relay NC and cause this non-control relay to be tie-energized and drop its contact fingers. The energization of the control relay CR would also cause 1ts contact finger 4-7 of the relay to be attracted, opening the shunt circuit through wires 45 and l6 l normal line phase current flowing in the track rails 1, the winding all of the main relay MR does not receive suiiicient energy to maintain the movable element ot this relay in its energized position. For this reason the mainrelay MR will remain in its deenergized position so long as the non-control push button NB is maintained depressed. lVith the main relay and the non-control relay NC both (lo-energized, the electropneumatic valve EPV is (ls-energized and an automatic brake application results. It the engineer or train operator now releases the non-control push button NB the control relay CR will be de-energized, retracting its contact fingers and 75. and the main relay MR will again be energized. The reenergization ofthe main relay MR will re energize the electro-pneumatic valve EPV through the contact finger 51 of this relay, and the train will be released from the automatic brake application and may again proceed until a caution or danger block is encountered. It is obvious from the above that an. automatic brake application will resultif the non-control push button NB is depressed while the train is proceeding in territory equipped for train control.

Now assume that a train has been brought to a stop by an automatic brake application in a caution block as described above, that the engineer has reset after the automatic stop and has proceeded to the next block in advance, which block is assumed to be a danger block, that is, a block in which another train is located or inwhich other dangerous trafiic conditions exist. The wheels and axles of the train in advance will shunt the track phase control current from the track rails. and the receiving coils 36 and 37 on the train under consideration will not receive energy from the rails. This will cause the de-energization of the main relay HR and a subsequent automatic stop in precisely the same manner as the automatic stop a which was imposed upon the entrance ofthc of trackway equipped for automatic train control, such as the block J shown in'the draw-' ings, and also assume that clear trafiic conditions exist, that is, that no train is located in advance of the train in question in the block J or in the next block in advance. Upon reaching the point in the trackway at which the'balance impedance 30 is located, the engineer, from his knowledge of the trackway, or by reason of a wayside indication, will know that he has reached the excess energy loop. The engineer will depress the non-control push button N B, energizing the control relav CB through the contact finger 52 of this push button. The energization of the control relay CR will attract its contact fingers 47 and 83. The attracting of the contact finger 47 will insert the resistance a l into the input circuit from the receiving coils 38 and 39, as described above, but as an excess amount of energy is supplied to the line phase circuit in this excess energy loop, the main relay MR will remain energized. The attracting of the contact finger 83 of the control relay CRwill close apick-up circuit to the non-control relay NC which may be traced as follows :From the battery terminal B, through contact finger 49 of the main relay MR, wire 84, contact finger 53 of the non-control push button NB, wire 85, contact finger 83 and the front contact of the control relay CR, Wires 86, 72 and 73, and the winding of the non-control relay NC to the battery terminal C. The engineer will maintain the non-control push button NB depressed until the train reaches the insulating joint at the end of the block J. At or about at this point, the engineer will release the non-control push button NB. Due to its slow acting characteristic described above, the non-control relay NC will not immediately retract its contact finger 77, and as the train passes into the non-control territory in the block K, its receiving coils 36 39 will fail to pick up energy from the track rails and the main relay MR will be de-ener gized.

With the main relay MR tie-energized, a

stick circuit to the non-control relay NC willthe electro-pneumatic valve thus energized,

and the non-control relay NC energized through its stick circuit, the train may pro ceed in the unequipped territory without the restrictions of the automatic control apparatus. It should be observed that the control relay CR is of the quick acting type, so that its contact finger 75, located in the stick circuit to the non-control relay NC will be re tracted immediately upon the de-energization of the control relay CR by the releasing of the non-control push button NB. Thus the noncontrol relay NC will be stuck up immediately on the entrance of the train into non-control territory, provided the non-control push button NB is released at the precise point at which the train enters such territory. The contact finger 54 of the non-control push button NB is made slow acting so that the energizing circuit to the electro-pneumatic valve EPV through this finger will not be broken while the train is traveling through the excess energy loop.

Assume that a train enters a clear block in which the auxiliary energizing section at the exit endot the block has for some reason hecome de-energized. As the line phase current in the block is supplied from the auxiliary energizing section through the current transformer 12, this line phase current will be cut off when the auxiliary section is deenergized, As the train enters a block-under these conditions, the main car relay MR will be de-energized and an automatic brake application will result, bringing the train to a stop. The engineer will know from the fact hat an automatic brake application occurred under a clear signal that the trackway circuits are out of order, and will report this fact at once, whereupon the diii'iculty may be remedied with the least possible delay in movements of traffic.

It has been found in practice that at certain points in trackwa-y territory which is unequipped for automatic train control, stray mirients flow for short distances in the track rails. These stray currents may be caused by leakage from adjacent track rails, or they may arise from any other cause. In a train control system of the type embodying this invention, where a polyphase main relay is used, these transient currents usually have no effect, for the reason that one phase winding only of the main relay is usually energized thereby. However, in certain cases, two such stray currents may occur in the track rails with such a phase displacement therebetween that the mam relay MR of the car-carried apparatus is" momentarily energized, or a single stray current in combination with the usual track phase current may cause such energization ot the relay MR. It is evident that such momentary energization of the main relay MR would cause its contact finger to disengage the stationary contact 67, thus breaking the stick circuit to the non-control relay NC. causing it to drop its contact fingers and to bring the train to a stop by an automatic brake application. In order to prevent such an automatic stop in unequipped territory due to the presence of stray currents extending for a limited distance along the track, the non-control relay NC is made slow acting as described above, the period of time required for this non-control relay NC to drop its contacts upon the de-energization of its windings being preferably arranged to be. as long as the time requireu for the train to pass over the longest stray current section ordinarily encountered in practice.

At certain points in territory which equipped for train control, sections of trackway are encountered over which it is diilicult to maintain a supply of train control current in the track railsv These sections may be cross-overs, switch frogs or similar trackway sections, where the rack rails are broken or where for any other reason it is dillicult to maintain the supply of train control current to the rails. If a train, equipped with an automatic control system of the type described, is traveling under clear tIflfllC conditions, that is with the main relay MR energized, and passes over one of these so called dead sections which only extend for limited distances, the main relay MB is momentarily (lo-energized, and its contact finger 51 disenits stationary contact 66. This would ordinarily cause the de-energization of the electro-pneumatic valve EPV, imposing an automatic brake application on the train. In order to prevent such automatic brake application while passing over such dead sections, the electro-pneumatic valve EPV is arranged to be slow acting, the period of such slow action being preferably made long enough so that the main relay MR may be deenergize=;l for the period. of time necessary to cover the longest of such dead sections ordinarily encountered in practice at an average train speed without causing an automatic brake a pplication.

It is to be understood that the particular circuits and devices described above have been selected, described and disclosed for the purpose of disclosing the nature of the invention rather than for the purpose of limiting its scope. t should be further understood that many changes, modifications and additions may be made without departing from the spirit of the invention. For instance, means for changing the connections to the receiving coils may be included, to enable the vehicle to proceed. with either end leading, speed control apparatus may he used for imposing more restrictive speeds upon the train after it proceeds into a caution or danger block, or many other additions, modifications and combinations may be made, all within the scope of the present invention.

\Vhat it is desired to secure by Letters Patent is 1. In an automatic train control system, trackway circuits for influencing car-carried brake control apparatus comprising track rails divided into blocks by insulated joints, a circuit for energizing a portion of each of said. blocks including a source of electrical .,cuit including the secondary winding of said transformer.

2. In an automatic train control system, in combination with car-carried apparatus for controlling the brakes of a train in response to control influences corresponding to traffic conditions and inductively received from the tracliway, a circuittor energizing a given section of traclrvray, and a second circuit for energizing a larger section of traclnvay including said first section, means for supplying electrical energy continuously to saidfirst circuit and means for delivering said electrical energ from said first circuit to said second circuit in accordance with trafiic conditions ahead.

car-carried control means for applying the brakes of a train in response to control influences corresponding to tralfic conditions inductively received from the trackwa y. and. means for su 'iplying said control influences to the traclrvvay comprising, an insulated section of the track rails, an energizing circuit for continuously supplying electrical ener to a part of said section, and a circuit for sup plying electrical energy from said part or said section to the remainder of said section under given traiiic conditions.

i. In an automatic train control system, the combination with car-carried control apparatus for applying the brakes of a train in response to control influences,traclrway apparatus for setting up said control in fluences comprising an insulated section of track rails supplied with electrical energy, said energy being continuously supplied to a portion of said section, and being transmitted from said portion to said entire section under given traffic conditions.

In an automatic train control system, vehicle carried apparatus including a relay and associated means for applying the brakes of the vehicle when said relay is ole-energized, means for energizing said relay in accord ance with electrical energy flowing in the track rails, a circuit for energizing sections of said traclr rails under favorable conditions, and short portions of said sections, constantly maintained energized from a mary source of electrical power, said sections ie track rails, a second circuit for energiza portion of said section, and a source oi electrical energy, said first circuit being at in r o. In an automatic train control system,

for energizing the entire length of a section times energized from said source of energy through said second circuit.

. 7. In an automatic train control system, car-carried brake control apparatusincluding a relay for bringing the train to a stop in. response to the'de-energization otsaid relay, means for controlling said relayv comprising, cs ving means and a traclnvay circuit-energized 0r tie-energized in accordance with traffic conditions ahead for in;

iluencing said receiving means, and a con"- stantly energized trackivay circuit for re-energizing said relay When once (lo-energized, said first trackway circuit being energized. from said constantly energized trackway circuit wher by a failure of the energy in said constantly energized trackway circuitwill affeet said car-carried brake control apparatus through the medium of said first mentioned trackway circuit.

8. In an automatic train control system, vehicle-carriedapparatus for bringing avehicle to. a stop in response to the cessation of control influences'received from trafiic controlled circuit under clear trafiic conditions ahead, a manually operable vehicle-carried device accessible only from the ground and acting when operated to render said brake control apparatus inactive, and a constantly energized section of trackway for transmit. ting control influences to return said brake control apparatus to its active condition, said trafiic controlled circuit being energized from said constantly energized section, whereby lack of energy in said constantly energized section will cause a cessation of control influences in said trafiic controlled circuit and Will bring the vehicle to a stop regardless of trafiic conditions ahead. i

9. In an automatic train control system of the type in which control influences corresponding to traffic conditions ahead are continuously set up by controlcurrent flowing in a controllable traclnvay circuit, vehicle-carried brake control means active to bringthe train to a stop upon the cessation of'such control current, manually operable means accessible only Wh en the vehicle is at a stop for rendering said brake control means inactive, and means for resetting said brake control means to its active condition comprising a permanently energized trackway circuit, the energizing circuit for-said controllable trackway circuit being supplied from said permanently energized trackway circuit in accordance with traffic conditionsahead, whereby lack-of energy in said. permanently energized track- Waycircuit will cause a cessation of the'con trol current in said controllable trackway circuit and bring the vehicle to a stop.

10. In an automatic train control system.

of the type in which control influences corresponding to traffic conditions ahead are continuously setup by control current flowing in a trackway control circuit, vehicle-carried brake control means active to bring the train to a stop upon the cessation of such control currents, manually operable means accessible only when the vehicle is at a stop for renderin g said brake control means inactive, means automatically operated in response to current flowing in a permanently energizedtrackway circuit for again rendering said brake control means responsive to currents flowing in said trackway control circuit in accordance with traiiic conditions ahead, and means for checking the integrity of said permanently energized trackway circuit.

ll. An automatic train controlsyst'em of he continuous inductive two-position type comprising, a car-carried electro-responsive bralre control means maintained energized under favorable trafiic'conditions ahead due to signal current flowing in the track rails ahead of the train, manually operable means operable only if the train is at a standstill and causing said brake control means to assume its energized position in the absence of signal current flowing in the track rails, and means at intervals along the traclrway effective to deenergize said brake control means When said brake control means is energized due to manual operation of said manually operable means, said last mentioned means being effective in spite of the vigilance of the engineer. 12. An automatic train control system of the continuous inductive two-position typecomprising, a. car-carried electro-responsive brake control means maintained energized under favorable traffic conditions ahead due to signal current flowing in the track rails ahead of the train, manually operable means operable only if the train is at a standstill and causing said brake control means to assume current flowing in the track rails, and means at intervals along the trackway effective to dec-nergize said brake controlmeans when said brake control means is energized due to manual operation of said manually operable means, said last mentioned means including a constantly energized circuit which is checked by means whereby failure of energy therein effect-s abrake application on the train in spite of favorable trafiic conditions ahead.

3. An automatic train control system of the continuous inductive two-position type romprising, a car-carried electro-responsive means maintained energized under favorable Era conditions ahead due to signal current flowing in the track rails ahead of the train. manually operable means operable only if the train is at a stop for causing said electro responsive means to assume its energized position in the absence of signal current flowing in the track rails, and means at intervals along the trackway effective to de-energize said electro-responsive means when said electroresponsive means is in its energized position 1 due to manual operation ofsaid manually its energized position in the absence of signal control device energized under farm-able traffic conditions ahead, manually operable means only accessible from the ground for energizing said brake control device and maintaining it energized under unfavorable tratiic conditions ahead, traclrway means at intervals along the traclrway for de-energizsaid brake control means When said brake control means is energized due to manual operation of said manually operable means, and means for protecting said manually operable means against misuse by including a normally closed contact of said manually operable means in the circuit of said brake control device, whereby the train cannot proceed until the manually operable means is placed in its normal condition.

in a train control system of the continuous inductive type, the combination with a normally energized brake control device on a railway vehicle which if de-energized effects a brake application, means responsive to current flowing in the track rails ahead of the train for maintaining said brake control. device energized under favorable trafiic conditions ahead, manually operable means only accessible when the train is at a stop for energizing said brake control device and maintaining it energized under unfavorable traffic conditions ahead, and trackway means at intervals along the trac-kway for de-energiz ing said brake control means when said brake control means is energized due to manual operation of said manually operable means, and means for checking the failure of said traclrway means.

16. In a train control system of the con tinuous inductive type, the combination with a normally energized brake control device on a railway vehicle which if tie-energized cf fects a brake application, means responsive to current flowing in the track rails ahead of the train for maintaining said brake control device energized under favorable traiiic covdfi tions ahead, manually operable means only accessible when the train is at a stop for energizing said brake control. device in a manner to maintain it energized under unfavor able traflic conditions ahead, and track ay means at intervals along the traclrway for deenergizing said brake control device when said brake control device is energized due to manual operation of said manually operable means, said trackway means being effective in spite of the vigilance of the engineer.

17. In a train control system of the continuous inductive type, the combination with a normally energized brake control device on a railway vehicle which if de-energized efl ects a brake application, means responsive to current flowing in the track rails ahead of the train for maintaining said brake control device energized under favorable traific conditions ahead, manually operable means only accessible when the train is at a stop for energizing said brake. control device in a manner to maintain it energized under unfavorable traffic conditions ahead, trackway means at intervals along the trackway for de-energizing said brake control device if said brake control device is energized due to having been placed in its energized condition by said manually operable means, and means for preventing said manually operable means from being left in its effective position permanently.

18. In a train control system of the continuous inductive type, the combination with a normally energized brake control device on a railway vehicle which if de-energized eflects a brake application, means responsive to current flowing in the track rails ahead of the train for maintaining said brake control device energized under favorable traflic conditions ahead, manually operable means only accessible when the train is at a stop for energizing said brake control device in a manner to maintain it energized under unfavorable traflic conditions ahead, trackway means at intervals along the trackway for de-energizing said brake control device if said brake control device is energized due tohaving been placed in its energized condition by said manually operable means, and car-carried visual indicating means for indicating whether said brake control device is energized by reason of favorable traffic conditions ahead or by reason of having been placed in its energized condition by said manually operable means.

19. In an automatic train control system, the combination with influence receiving coils on the vehicle in inductive communication with the track rails, a main relay maintained energized in response to currents flowing in the track rails through the medium of said coils, a brake control device energized if said main relay is energized, a stick relay which if energized maintains said brake control device energized, means including a manually operable device in the cab and excessive currents in the track rails for picking up said stick relay, and separate manually operable means accessible onl from the ground for picking up said stic relay.

20. In an automatic train control system, the combination with influence receiving coils on the vehicle in inductive communication with the track rails, a main relay maintained energized in response to currents flowing in the track rails through the medium of said coils, a brake control device energized if said main relay is energized, a stick relay which if energized maintains said brake control device energized, a stick circuit for said stick relay including a front contact of said stick relay and a contact of said main relay closed only if said main relay is de-energized, manually operable means only accessible when the train is at a stop for picking up

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