US2528052A - Supplemental signaling system for - Google Patents

Description

Oct. 31, 1950 w. v. GROSJEAN SUPPLEMENTAL SIGNALING SYSTEM FOR SPECIAL RAILWAY VEHICLES 7 Sheets-Sheet 1 Filed Jan. 29, 1948 m U NTQJQ E g mm 1 Ln fi 1 win k a $5M NEWS 3 JJ Kw A 1 i MN m 51 EN mmafi w ME m M lwfllwll Ill Q Ew m mw EMS Mw Em INVENTOR. Wba Ifflnogemz. BY

H15 47 mm IIIIIIIIIL MMN Evaxwh Oct. 31, 1950 w. v. GROSJEAN 2,523,052

SUPPLEMENTAL SIGNALING SYSTEM I FOR SPECIAL RAILWAY VEHICLES 7 Sheets-Sheet 2 Filed Jan. 29, 1948 IN VEN TOR.

gdrajean.

Hrs" ATTORNEY Wi'lb Ev RETN 5m 5m H J Oct. 31, 1950 w. v. GROSJEAN SUPPLEMENTAL SIGNALING SYSTEM FOR SPECIAL RAILWAY VEHICLES 7 Sheets-Sheet 3 Ev Em EBB IERA Filed Jan. 29, 1948 Maw , wwvk NNNH O INVENTOfi. {Wilbur GPosyemz BY g Oct. 31, 1950 w. v. GROSJEAN 2,528,052

- SUPPLEMENTAL SIGNALING SYSTEM FOR SPECIAL RAILWAY VEHICLES Filed Jan. 29, 1948 7 Sheets-Sheet 4 a m ENE INVENTOR. V Mlbuv Grogyean.

Hi5 ATTORMZ'Y Oct. 31, 1950 Filed Jan. 29, 1948 W. V. GROSJ EAN SUPPLEMENTAL SIGNALING SYSTEM FOR SPECIAL RAILWAY VEHICLES 7 Sheets-Sheet 5 IN VEN TOR.

Wz'lb V. 600959072 HIS ATTORNEY '7 Sheets-Sheet 6 W. V. G ROSJEAN SUPPLEMENTAL SIGNALING SYSTEM FOR SPECIAL RAILWAY VEHICLES INVENZOR. Mlfia Gnageazz.

[/15 ATTORNEY www mi BMV Oct. 31, 1950 Filgd Jan. 29, 1948 Filed Jan. 29, 1948 Oct. 31, 1950 2,528,052

4 W. V. GROSJEAN SUPPLEMENTAL SIGNALING SYSTEM FOR SPECIAL RAILWAY VEHICLES 7 Sheets$heet 7 INVENTOR. v Wilbur V z ayean H15 A TTORNHY' Patented Oct. 31, 1950 SUPPLEMENTAL SIGNALING SYSTEM FOR SPECIAL RAILWAY VEHICLES Wilbur V. Grosjean, Gmaha, Nebr., assignor to The Union Switch and Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application January 29, 1948, Serial No. 5,138

8 Claims.

My invention relates to supplemental signaling systems for special railway vehicles, and particularly to improved systems of the type de scribed adapted to be used in stretches of single track railway equipped with a principal signaling system which is manually controlled from a central ofice.

Special railway vehicles, such as small motor cars used by maintenance personnel, are usually equipped with insulated wheels or axles so that these cars do not shunt the track circuits by which block signaling systems for controlling train movements are conventionally controlled. As a result, such systems ordinarily do not indicate the presence of a motor car. Accordingly, no protection is afforded to the motor car and its operator by the conventional block signaling systems.

In my copending application for Letters Patent of the United States, Serial No. 996, filed January '7, 1948, there is shown a supplemental signaling system for governing indicators on special railway vehicles, which system may be applied to a track stretch equipped with an automatic block signaling system.

It is an object of my invention to provide improved means of the type described which may be applied to a stretch of single track railway equipped with a principal signaling system of the type in which the wayside signal apparatus is manually controlled from a central o-flice so as to prepare each track stretch for train movements at times in one direction and at other times for train movements in the other direction.

Another object of my invention is to provide improved means of the type described which employs currents of a distinctive character in the track rails for the control of the special vehicles and which is incapable of interfering with the L operation of the principal signaling system.

A further object of my invention is to provide means of the type described which may be applied to existing railway block signaling systems with a minimum of additional apparatus.

Still another object of my invention is to provide a supplemental signaling system for governing indicators on special railway vehicles which will operate to warn the operator of the vehicle of the approach of a train in ample time to allow removal of the vehicle from the track.

A further object of my invention is to provide a supplemental signaling system for governing indicators on special railway vehicles which will provide the operator of such a vehicle with corn '2 tinuous information concerning traffic conditions in a stretch of railway over which the vehicle is operating.

Another object of the invention is to provide means efiective when a train is approaching a single track stretch which is occupied by a motor car for indicating the approach of the train to the operator of the motor car only in the event that the train is authorized by signal indication, to enter the stretch, with the advantage that the operation of the motor car is not interfered with by the approach of a train which is not authorized to enter the single track stretch and therefore does not represent a hazard to the motor car.

A further object of the invention is to provide indication means of the type described which is governed by the wayside signaling apparatus in such a manner that the indicator on the motor car is controlled in accordance with the condition of the head block signal at the entrance end, for the established traific direction, and by traffic approaching that signal, so as to provide a warning indication on the motor car when a train is approaching the entrance end of the single track stretch only if this train is authorized to enter the stretch. This warning indication is provided in ample time to enable the motor car to be removed from the track, if the train is authorized to enter the single track stretch.

Other objects of my invention and features of novelty will be apparent from the following description taken in connection with the accompanyin drawings.

I shall describe two forms of supplemental signaling systems embodying my invention and shall then point out the novel features thereof in claims.

In the drawings, Figs. 1A, 1B, and 10, when placed together in the order named with Fig. 1A at the left, form a diagram of a stretch of single track railway equipped with wayside signaling apparatus embodying my invention, and

Figs. 2A, 2B, and 2C, when placed together in the order named with Fig. 2A at the left, form a diagram of a stretch of single track railway equipped with wayside signaling apparatus and embodying a modification of my invention which I may employ.

Fig. 3 is a diagrammatic view of a preferred form of indication equipment which may be applied to a railway motor car to be used in cooperation with the wayside apparatus of my invention, and is similar to that shown and Clea 3 scribed in my copending application, Serial No. 996.

In practicing my invention the trafific relays which are located at the opposite ends of each single track stretch and are governed from a central ofiice to cause the wayside signal system to establish traffic in one direction or the other are employed to govern means for supplying current of a distinctive character to the rails of the single track stretch, such as alternating current of a selected frequency, for example, to thereby govern indication means on motor cars in the single track stretch. The supplementary signaling system is so controlled that when a single track stretch is set up for trafiic in either direction, the suppl of current of distinctive character to the rails of the track stretch is governed from the corresponding entrance end of the stretch.

The means for supplying the motor car control current to the entrance end of each single track stretch is also governed by the head block signal at that end so that when the head block signal is at stop, thereb preventing entrance of a train into the stretch, motor car control current will be supplied to the rails of the single track stretch regardless of trafiic conditions in the stretch approaching the head block signal. On the other hand, when the head block signal is cleared to authorize entrance of a train into the single track stretch, the supply of motor car control current to the rails of the single track stretch is governed by traffic conditions in the stretch approaching the head block signal so that a motor car present anywhere in the single track stretch will have adequate warning of the approach of a train.

In one form of the invention alternating current is supplied to the rails of the stretch at the entrance end and is cascaded or repeated from section to section to the exit end of the stretch so that alternating current is supplied to all of the sections in the stretch if the stretch is unoccupied, or is supplied to the sections in the stretch behind a train if the stretch is occupied.

In a modification of the invention a special line circuit controlled by trafiic conditions in the stretch extends the length of each single track stretch and governs relays which control the supply of alternating current to the rails of the various sections in the stretch. Energy is supplied to this line circuit at the entrance end of the stretch and controls the relays energized therefrom to cause alternating current to be supplied to the rails of all of the sections in the stretch if the stretch is unoccupied, or to be supplied to the sections in the stretch behind a train if the stretch is occupied.

This invention also includes means for controlling the supply of alternating current to the rails of the main track portions adjacent the passing sidings in such manner that alternating current is supplied to the rails of each of these track portions when the signals governing entrance of trafiic into the main track portion are held at stop, while the supply of alternating current to the rails of one of these track portions is cut oil when a signal is cleared to authorize entrance of a train into the track portion.

Referring to Figs. 1A, 1B and of the drawings, there is shown therein a stretch of single track railway extending between two passing sidings PS. This stretch is provided with wayside signal apparatus governed from a central oiiice through a conventional centralized traflic control system for authorizing trafiic to move in one direction through the stretch at times and to move in the other direction at other times. In the present application only the portions of the wayside apparatus essential to the under-' standing of my invention have been shown, and theremainder of the equipment may be arranged as shown in Letters Patent of the United States No. 2,424,038, granted to Arthur L. Jerome on July 15, 1947.

As shown, the wayside signals are of the wellknow Searchlight type and may be constructed as shown in Letters Patent of the United States No. 1,864,224, granted on June 21, 1932, to Wesley B. Wells.

The equipment at the left-hand or west end of the stretch includes a code controlled field station unit of the centralized traffic controy system, designated station 1-2, and the equipment at the right-hand or east end of the stretch includes a similar field station unit designated station 3-4. Inasmuch as my invention relates to wayside apparatus, it is deemed sufficient to point out that the field station units are connected to a control ofiice by a line circuit not shown, over which control codes may be transmitted to the field stations one at a time. The control codes transmitted to these stations serve to operate a group of control relays of the stick polar type, in accordance with the positions of control levers at the office. Three such control relays are shown herein at each station andthese comprise a trafiic relay, such as relay ZWFSR, Fig. 1A which governs the direction of trafiic movement in the single track stretch by cooperation with a similar rela 4EFSR at the opposite end of the single track stretch, shown in Fig. 1C, and also includes two code controlled signal control relays, such as the relay ZRHSR or ZLHSR, in Fig. 1A, by which the clearing of the correspondingly designated signals is made subject to manual control from the omce.

Each trafiic relay 2WFSR. or llEFSR, when in its normal position, with its left-hand contacts closed, designates its location as the exit end of the stretch. In this position, the trafiic relay supplies energy to the reversible signal control circuits for the single track stretch to enable the signals which govern traific movements toward this location to be cleared. Each traific relay when reversed, with its right-hand contacts closed, designates its location as the entrance end of the single track stretch, in which position the traffic relay enables the associated entering head block signal to be cleared, under proper conditions, in response to the reversal of the associated code controlled signal control relay ZRHSR or GLHSR. The traific and signal control relays are controlled in a manner fully described in the above-identified Jerome patent, and it suffices to point out that these relays are controlled so that when relay ZW'FSR is operated to its normal position, relay EFSR is operated to its reverse position, and vice versa, so that the direction of trafiic is in one direction at times, and in the other direction at other times.

On each of the motor cars or special vehicles which may be operated through the stretch there is provided apparatus which is responsive only to the presence of alternating current energy in the rails over which the vehicle moves.

Referring now to Fig. 3, there is shown a diagrammatic View of one arrangement of indication apparatus which may be employed on motor or other special cars which are operated over the not shunt the track circuit. A slip ring SR!" makes electrical contact with the wheel WI and a second slip ring SR2 makes electrical contact with the wheel W2. Connected in series between the slip rings SR] and SEE are the condenser IQ and the primary winding of a transformer IT. The secondary winding of the transformer IT is connected to the input terminals of a bridge-type rectifier IRX, and the winding of an indicator relay IR is connectedL across the output terminals of this rectifier. It will be apparent that when the car moves over the rails of a track section the condenser IQ will prevent the flow or direct current track circuit energy, but will permit the flow of alternating current through the primary winding of the transformer IT. The alternating current induced in the secondary winding of transformer IT is rectified by rectifier IRX, and is supplied to the winding of relay IR, and as a result, relay IR picks up to establish a circuit, obvious from the drawing, for supplying energy over its front contact from the battery IE to light the indicator lamp KE. If the supply of alternating current to the rails R is interrupted, energy will no longer be supplied to the winding of relay IR and its contacts will release, extinguishing the lamp and establishing a circuit for supplying energy to a warm ing bell KS. A switch SW is shown in series with the circuit for supplying energy to the indication lamp KE and the warnin bell KS, so that the equipment may be deenergized when the car is removed from the rails.

It is to be understood that my invention is not the rails, together with an amplifier for amplifying the energy induced in such coils, such an arrangement being well-known from its use for the control of train carried cab signals.

The trackway system includes continuous direct current track circuits for all main tracks. Each of the track sections IT, 2T, 3T, GT, 5T, 5T, IT and BT has a conventional direct current track circuit including a track battery TB and a track relay TR.

Additionally, at the relay end of each track circuit section, the secondary windin of a track transformer TT is connected across the rails of the section. When alternating current is supplied to the primary winding of the track transformer, alternating current induced in the secondary winding is supplied to the rails of the section. The winding of the track relay presents a high impedance to the alternating current so that the flow of alternating current through the winding of the track relay is negligible. Accord ingly, it is apparent that alternating current may be supplied to a track circuit section without afiecting the operation of the direct current track circuit.

Energy for t. operaiien of the relays other rupt the circuits for supplying energy to e sesgose 6, than the track relays is furnished by suitable sources of direct current, notshown, whose. positive and negative terminals are designated B and C, respectively. Additionally, there is provided a source of alternating current energy whose terminals-aredesignated BX and (3X.

' In most instances in the drawings the relay contacts are located directly in line with the winding of the relay, but in some cases in order to' simplify the drawings, relay contacts are separated from the relay windingand in these instances. the relay with which the contacts are associated is identified by appropriate reference characters placed above thecontacts.

As previously explained, the principal signaling system shown in the drawing is similar to that shown and described in the above-identified Jerome patent, but to clarify the drawings the additional circuits and apparatus employed in connection with my invention have been shown by heavier lines.

Referring to Fig. 1', the equipment is shown in the condition which it assumes when the single track stretch i vacant, the signals 2B. and 4L are at stop, and the reversible line circuit system for controlling the signals is set up in the direction for right to left, or westbound trafiic movements. At this time, the contacts Ziland 2! of the tranic relay ZWFSR at the left-hand or west end of the stretch are in their left-hand or normal position and connect line wires 23 and 24 over contacts 25 and 26 of a pole-changer or repeating relay 2LPC for signal 2L and through the winding of an approach relay ZLAR to terminals B and C of the local source of energy. The relay ELPC is governed in the well-known manner in accordance with the aspect displayed by signal 2L and controls the polarity of the energy supplied to the line wires 23 and 24. As shown the signal 2L is assumed to be at stop so the relay ZLPC is released and causes the energy supplied to the line wires 23 and 24 to be of reverse polarity. The energy supplied to the line wires 23 and 24 feeds over front contacts of track relays ITR, ZTR, and lTR, over back contacts 2i and 28 of a repeating relay (SRPC, for signal 5R, Fig. 1B, and back contacts 30 and 3| of a directional stick relay GRSR to the winding of the mechanism for signal 6L, and causes this signal to display its yellow or caution indication, while the flow of this energy through the winding of relay 2LAR causes this relay to assume its energized position as shown.

Since signal 6L is now conditioned to display its caution indication, energy is supplied over the front contact Y of its mechanism to its repeating relay BLPC, the contacts of which are picked up to cause energy of normal polarity to be supplied to line wires and 4! leading to relay liLHD. At this time wire ii is connected to terminal C over front contact 42 of relay tLPC, and wire it is connected over front contact Q3 of relay BLPC to terminal B at the back contacts G and Y of the mechanism for signal GB.

The energy supplied to line wires 40 and 4| is supplied over front contacts of track relays 5TB, ETR, and 3TB, and reverse polar contacts and 5! of the traffic relay lEFSR to the winding of a line relay ALI-ID for signals ihA and dLB, and causes relay Ll-ID to close its neutral front contacts and to move its polar contacts to their lefthand or normal position. As shown, the contacts c5 and 5? of the signal control relay 4Ll-ISR. are in their normal position and inter- '7 windings of signals 4LA and 4L3 so that these signals are both at stop and their mechanism contacts establish a circuit for energizing a signal indication relay lLRGP so that its contacts are picked up.

Relay IRI-ID is a polarized line relay which controls signal 4R by means of circuits governed by signal control relay lRl-lSR. The circuits are not shown, but are to be understood to be similar to the circuits for controlling signals ILA and 4LB. By placing Fig. 1G to the left of Fig. 1A, the arrangement of circuits for controlling relay QRHD may be traced. As shown, relay lRHD is governed by a two-wire line circuit extending between the ends of the passing siding and the circuit includes front contacts of relays 3TB, 'ITR, BTR, and ITR, so that when a train occupies any portion of the main track between signal GR and signal 2L, relay iRl-ID will be released. Additionally, a front contact of a signal indication relay ZLRGP is included in the circuit for relay lRl-ID, the relay ZLRGP being governed over a circuit similar to that for relay 4LRGP but controlled by signal 2L so that its contacts are picked up when and only when signal 2L indicates stop. Accordingly, when signal 2L is cleared for a train moving from right to left to permit the train to enter the main track stretch between signal AR, and signal 2L, relay 2LRGP will release and interrupt the circuit of relay 4RHD so that signal 4R cannot be cleared, thus providing protection against opposing train movements. The polarity of the energy supplied to relay tRI-ID is governed by pole changing contacts of the pole changer relay ZRAPC for signal ZRA so a to cause the aspects displayed by signal 4R. to be dependent upon the aspects displayed by signal ZRA.

Relay ZLHD is a polarized line relay controlled in a similar manner by a two-wire line circuit which is arranged in the same manner as the circuit for relay QRHD, but oppositely directed, and cooperates with relay ZLHSR to govern circuits, not shown, for controlling signals 2L.

Under the condition being described, rlternating curent is supplied to the primary winding of transformer 3TT by the circuit which is traced from terminal BX at front contact III of relay lLI-ID, over front contact I I2 of relay GRHD, and through the primary winding of transformer 3TT to terminal CX. As a result, alternating current is induced in the secondary winding of transformer 3TT and is supplied to the rails of the detector track section 3T, and over the rails of section 3T to a first winding of transformer 3'TT which is connected across the rails of section 3T in series with track battery 3TB. Transformer 37TT is transformer having a turns ratio of 1 to 1, so that current is induced in its second winding which is of substantially the same value as that supplied to the first winding. Accordingly, the alternating current supplied to section 3T causes alternating current to be supplied through the transformer 3-ITT to the rails of section IT. A reactor in series with the track battery 'I'TB prevents excessive flow of the alternating current through the battery 7TB, and although the track relay 'ETR is effectively connected across the second winding of transformer 3-7TT, the direct current track relay winding presents a relatively high impedance to the alternating current so that very little of the alternating curent flows through the relay winding.

Alternating current is. also supplied to the primar winding of transformer GTT at this time by a circuit which is traced from terminal BX, over front contact II l of track relay 'ITR in multiple with a front contact IIS of a flasher relay lCT, over front contact IIl of relay GTR, over front contact I I9 of relay GLRGP in multiple with a front contact I2! of relay flRHD, and a normally closed switch correspondence contact I22, over reverse polar contact I23 of relay AEFSR, over front contact I25 of relay 3TH, and through the primary winding of transformer BTT to terminal CX. The flasher relay iCT has its operating winding continuously connected to the direct current source and is of the type having contacts which are recurrentl picked up and released at an appropriate rate, for example, times per minute. When contact Il t of relay lTR is picked up, alternating current is continuously supplied to the primary winding of transformer STT over the circuit traced above, but when contact I it of relay lTR is released, the supply of alternating current to the primary winding of transformer STT is periodically interrupted by contact IE6 of relay CT.

Accordingly, at this time alternating current is supplied from the secondary winding of the transformer GTT to the rails of section GT, and feeds over the rails of section BT to the first winding of the transformer 5-6'I'I, Fig. 1B, which is similar to the transformer 3-ITT. The alternating current supplied to the first winding of the transformer 5BTT induces similar alternating current in the second winding of the transformer 5-5TT from which current is sup plied to the rails of section 5T.

At this time track relay ETR is picked up, and relay ELPC is picked up, and a circuit is established to connect the primary winding of transformer BZT across the rails of section ET. This circuit is traced from the upper rail of section 5T, over front contact IZ'I of relay GLPC, through the primary winding of transformer EZT, over front contact I28 of relax BLPC, and over front contact I29 of relay 5TB to the lower rail of section 5T, The alternating current supplied to the primary winding of transformer BZT induces alternating current in the transformer secondary winding and this current is rectified by the fullwave rectifier BZK and is supplied to the winding of an indicator control relay BZR. As a result, the contacts of relay SZR are picked up. The relay 62B is of the type which is slow in releasing its contacts, and is arranged so that its contacts will remain picked up if recurrent pulses of energy are supplied to its winding at a certain rate, for example, '75 times per minute. When relay SZR. is picked up, its contact I3I in the circuit for supplying current to the primary winding of transformer STT is closed, but this circuit is interrupted by back contact $34 of relay GLPC, sothat no alternating current is supplied to the primary winding of transformer ETI at this time. When contact E32 of relay 62R is picked up, it establishes the circuit for supplying alternating current to the primary winding of transformer 4T1, which circuit is traced from terminal BX over front contact I32 of relay BZR, through the primary winding of transformer GTT, and over back contact I35 of relay BRPC, to terminal CX.

The alternating current induced in the secondary winding of transformer QTT at this time is supplied to the rails of section AT and feeds over the rails of section 41 to a winding of transformer 2 --41"l; by a elrcuit which is traced from the right-hand terminal :of :the secondary winding of transformer :iiT'I, over back contact 13% of relay.6RPC,.over the upper rail of section 4T, through the first windingof transformer Fi 'TT, through batter lTB, over the lower rail of section .51, over front contact 138 of relay and over back contact E39 of relay BBPC to the left-hand terminal of the secondary winding of transformerdTT. Accordingly, it will be seen that the current induced :in the secondary winding of transformerAiiT is supplied-over the rails of section 4T to the first winding of transformer 2 iTT, and as a result alternating current is induced in the second winding of transformer 2-HT and is supplied therefrom to the rails of section 2T.

At this time, since traffic relay 2WFSR, Fig. 1A, is in its normal position, its contact M interrupts the circuit for supplying alternating current to the primary winding of transformer ZTT, but as explained above, alternating current is supplied to the rails of section 2T from the second winding of transformer 2---4TT.

Alternating current is supplied to the primary winding of transformer alTT at this time by the circuit which is traced from terminal BX, over front contact I42 of relay ZLAR, over normal polar contact I43 of traffic relay .ZWFSR, over front contact 1.45 of relay ELI-ID, and through the primary winding of transformer ITT to terminal OX. The alternating current induced in the secondary winding-of transformer ITT is supplied over the rails of the detector track section l'I to the first winding of transformer l-BTT, and the alternating current energy induced in the second winding of transformer l--8TT is supplied to the rails of section 8T.

From the foregoing it will be seen that under the condition described, that is, when there is no train in the vicinity of the single track stretch and the reversible line circuit system is set up in the direction required for a train movement from right to :left, alternating current is supplied to the rails of the stretch at the entrance end, and is cascaded through section by section to the exit end of the stretchysothat alternating current is supplied to each of the track sectionsi If a motor car having insulated wheels and equipped with suitable means for indicating the presence of alternating current in the track rails, such for example, as is shown in Fig. 3, traverses the block, the indication means on the motor car will indicate the presence of alternating current in each of the track sections to thereby indicate to the operator of the car that he may proceed safely.

It will now be assumed that a train moving from right to left, that is, westbound, approaches the right-hand or entrance end of the stretch. 1

Accordingly, due to the release of one or more of the track relays which control its circuit-the line relay ARI-ID will be deenergized and its neutral contacts will release. Due to the release of relay @RHD, its contact lZI in the circuits for supplying alternating current to the transformer ETT is open, but as it is assumed that signal ELA or l-L'B has not been cleared the relay remains picked up and its contact H9 maintains the supply of energy to transformer and thus maintains the supply of alternating current to the rails of all of the track sections in the single track stretch. Accordingly,

indication means on a motor car present anyindication that it is safe for the car toremain v on the track rails.

Even though a westbound'train has approached the entrance end-of the single track stretch, it is evidently safe for the motor car to remain on the rails of the single track stretch when the head block signals v iLA and 4LB governing entrance of a westbound train into the track stretch are held at stop so as'to prevent the approaching westbound train from entering the single track stretch.

If the approaching westbound train should over-run the .head block signal ALA ,or 4L3 and enter the single track stretch without authority, it would,.as hereinafterexplained, cutoff the supply ,of alternating current to the entrance .end of the stretchand thus .cut off the supply of alternating current to .the track rails throughout the stretch so that the indication means on a motor car present anywhere in the stretch would then warn the operatorof the motor car of the approaching train.

At this time, as it is assumed that the wayside signal system has been set up for .westbound traffic, the head block signals .ZRA and 2R3, which govern-entranceof eastbound traffic into the stretch-are held atistop and cannot be cleared. Hence eastbound trains are prevented from entering the single trackstretch, and it is only necessary to protect theoperators of motor cars from approaching westbound trains.

When front-contact N2 of relay dRHDreleases, it interrupts the circuit previously :traced for the primary winding of transformer 3TT, and as a result, the supply of alternating :current to the rails of the detector track section 131 is .cut oil. Since energy is -no'longer supplied .to the primary winding of transformer :3--'lTT, .there'is no .alternating current induced in the secondary winding of the transformer, andas a result .no-alternating current is supplied to the rails of section ET at this time.

Accordingly, a motor car moving through the stretch from left to right, receives alternating current from the track sections v-of the single trackstretch including section 5T, but when the motor car advances :into sections 3T and IT, no alternating current will be received from the section rails, :and the apparatus on the motor car will indicate thata train is approaching, so that the operator-can remove the car from the rails.

"Whenthe approaching westbound train enters section Tl], track relay 'lTR releases and its front contact H 3 interrupts thesupplyofsteady alternating cur-rent to transformer tT-T, and alternating current is now recurrently supplied to transformer fiTT over the circuit including contact -ll of-flasher relay ACT. As a result,impulses ofalternating currentare recurrently sup- :plied totherails of section GT, and through the transformer -5- 6TT .to the rails of section ET, and are rectified and supplied to the winding of relay 62R. As previously explained, the relay ,GZR-is of the slow release type, and willnot re- :lease its contacts at this time. As a result, the supply of alternating current energy to transformer iTT is maintained at this time.

From the foregoing ;it-will be seen that, at this time, the apparatus on a :motor car moving from left to right :will receive steady alternating current until the motor car enters section 5T and zfiT, at which time the recurrent impulses of alternating currentwill cause the apparatus on the where in the single track stretch will provide an T5 mqtorcar to operate periodically, totherebywarn the operator that a train is approaching, but is not yet in dangerous proximity to the motor car.

It will now be assumed that the central office operator causes a control code to be transmitted to field station 3& to clear signal tLA and thereby authorize the approaching westbound train to enter the single track stretch. This control code causes the contacts of relay dLI-ISR to be operated to their reverse or right hand position. On reversal of the contacts 58 and 53 of relay ALHSR, energy is supplied from terminals B and C of the local source to the winding of signal ALA over the circuit controlled by neutral and polar contacts of relay 4LHD, and by contacts 99 and 91 which are governed in accordance with the position of the track switch SW and of the control relay therefore so as to establish the circuit of signal ALA when and only when the track switch and its control relay are in their normal position. As shown, the switch 3W is in its normal position and the polar contacts of the line relay lLI-l'll) are in their normal position so that energy is supplied to the winding of signal ALA to cause it to display its green of proceed indication. When signal ALA clears, the circuit of relay ALRGP is interrupted and its contacts release. When front contact H9 of relay ALRGP releases, the supply of alternating current is cut off from the primary winding of transformer 5T1, since contact I21 of relay ARHD is already r leased. Accordingly, the supply of alternating current to the rails of section ST is interrupted, and the supply of alternating current through transformer 58TT to the rails of section ET and over the circuit previously traced to the primary winding of transformer 6ZT is interrupted. As a result, energy ceases to be supplied to the winding of relay GZR, and its contacts release. When contact l32 of relay BZR. releases, it interrupts the circuit previously traced for supplying alternating current to the primary winding of transformer 4T1, with the result that alternating current is no longer supplied to the rails of section 4'1, and therefore ceases to be supplied over the rails of section 4T to the first winding of transformer 24TT, so that alternating current is no longer supplied from the secondary winding of transformer 2ATT to the rails of section 2T.

From the foregoing, it will be seen that when the signal ALA is cleared for an approaching train, and the train has caused relay iRHD to be released, the supply of alternating current is cut off from the rails of all of the sections in the single track stretch, so that a motor car traveling through the stretch does not receive alternating current and the indication apparatus carried by the car thereby informs the operator that a train is approaching.

In the event the central ofiice operator clears signal ALA before relay ARHD is released by the approaching train, relay ALRGP will release, but the supply of energy to transformer BTT will be maintained by front contact [21 of relay ARI-ID and switch correspondence contact I22. When the signal 2L at the right hand end of the passing siding PS is cleared, or when the approaching train enters section IT at the right hand end of the siding, relay 4RI-ID releases and the supply of alternating current to transformer iiTT is cut off, with the results described above.

If a westbound train occupying the side track approaches signal ALB, the supply of energy to transformer B'IT will continue as long as signal ALB remains at stop, but When the switch 3W is reversed prior to clearing signal ALB, contact 22 is opened, so that when signal 4LB is cleared and relay QLRGP releases, its front contact H9 interrupts the supply of energy to transformer STT and, although front contact I21 of relay lRHD is closed, contact I22 interrupts the circuit so that no energy is supplied to transformer BTT at this time.

Accordingly, it will be seen that the motor car operator will be provided with a clear indication until such time as traflic conditions require the clear indication to be cancelled.

When signal ALB is cleared, and also when signal ALA is cleared and relay ARHLD is released because of the approach of a westbound train on the main track at the right hand end of the single track stretch, the supply of alternating current to the primary winding of transformer lTT, Fig. 1A, at the left hand end of the single track stretch is maintained by the circuit previously traced, and accordingly, alternating current is supplied to sections IT and 8T, at the left, as previously described. It will be apparent, therefore, that an eastbound motor car traveling through sections 87. and 1T will have its indication apparatus energized until the motor car enters the first section 2T of the single track stretch, when the absence of alternating current will cause the apparatus on the motor car to indicate that a train is approaching the opposing entering signal at th right hand end of the single track stretch.

When a westbound train accepts signal ALA or ALB and enters the detector track section 3T, the track relay 3TB, releases to interrupt the circuit of relay ALHD, While a contact of relay 3TH interrupts a circuit of the slow release relay .iTP. After release of relay 3TB and prior to release of relay 3TP, energy is supplied over back contact 12 of relay 3TB. and front contact 13 of relay 3TP to the lower winding of relay ALI-18R and moves the relay contacts 58 and 59 to their nor mal positions in which they interrupt the circuit of signal ALA to prevent reclearing of signal ALA unless th contacts of relay 4LI-ISR are reversed by a control code transmitted from the office.

When signal ALA displays its stop indication, relay flLRGP is energized and its front contact H9 in the circuit for the primary winding of transformer STT is closed, but this circuit is interrupted at this time by front contact I25 of relay 3TB. It follows that when the train enters the stretch and returns signal ALA to stop, alternating current is not supplied to the rails of the track stretch in advance of the train and consequently the indication means on a motor car present in the single track stretch will display its danger indication.

As the westbound train advances into sections ST and ET, the track relays 5TB, and ETR release to interrupt the line wires All and Al and thus maintain relay ALHD deenergized. Front contact H! of relay 6TB, additionally interrupts the circuit for the primary winding of transformer BTT, and front contact l29 of relay 5TB interrupts the circuit for connecting the primary winding of transformer BZ'I to the rails of section 5T.

When the rear of the train vacates section 37., the track relay 3TR picks up, and its front contacts again establish a circuit for relay 4RHD, and its contacts pick up.

When the rear of the train vacates section 5T, track relay 6TB picks up, and its front contact H'i completes the circuit for the primary winding of transformer BTT so that alternating current is supplied to the rails of section 6T. Asa result, a motor car following the train under .discussion will receive alternating current from the rails of section 6T as the train progresses so the motor car operator may safely follow a train through the stretch. However, the shunting effect of the wheelsand axles of the train prevents the alternating current from reaching the rails ahead of the train.

When the train enters section GT, the track relay 4TB releases and energy is supplied to relay BLSR, over the circuit which includes back contact 89 of relay 4TB and front contact 85 of relay GLPC. Accordingly, relay .SLSR picks up and establishes for itself a stick circuit which is .efifective as long as either relay ITR or relay .ELPC is released.

On release of relay 'dTRthe supply of energy over line wires 23 and to the mechanism for signal BL is cut off and the signal displays its stop indication and interrupts the circuit of relay ELPC and it releases so that energy of reverse polarity is supplied to the line wires ii) and ii over back contacts 43 and 320f relay QLPQ'front contacts of relay GLSR, and back contacts G and Y of the mechanism for signal 6B.

When relay 4TB releases and interrupts the circuit for signal 6L, the series approach relay 2LAR, Fig. 1A, in that circuit releases and-opens its contact M2 which cuts off the supply of alternating current from the primary winding of transformer ITT so that alternating current is no longer supplied to the rails of section iTT and is no longer supplied over the rails of section 2T to the winding of transformer i-8TT. As a re sult, alternating current is no lcnger'supplied to the rails of section IiT.

It will be seen, therefore, that when a west bound train advances into section tT'the supply of alternating current to the rails of sections l1 and ST in the main track portion beside the passing siding PS in advance of the train is cut off so that the indication means on a motor car present in either of these sections will warn of theapproach of the train.

When th westbound train vacates sections ET and ET, the track relays "BTR and 5TB. pick up and complete the circuit for the line wires ii! and II and energy is supplied to relay lL'HD to pick up its neutral contacts and move its polar contacts to their right-hand or reverse position, so that, if the contacts of relay 4LHSR are reversed to clear signal. dLA, this signal will display its yellow or caution indication.

When relay lLI-ID picks up, its front contact 3 7 I! l in the circuit for supplying .energy to the primary winding of transformer :3TT is again closed.

Additionally, when relay :5TR picks up, its

front contact I213 establishes the circuit which includes back contacts I2] and I28 of relay SLPC for connecting the secondary winding of transformer 5TT to the rails of section 5T. However, at this time, no energy is supplied to'rela BZR and its contacts are released. Contact '13! inter- When the train-vacates section 4T, track relay M bound train to pass out of the single track stretch, the train may advance into section IT, so that relay lTR releases and in turn, releases relay 'ZLHD, contact I of which furtherinter- :rupts the circuits for supplying alternating current to the rails of sections IT and 8T.

When signal '2L is cleared, rela 2LRGP releases, and, as will be clear by placing Fig. 1C

at the left of Fig. 1A, the release of relay ZLRGP opens the circuit for the signal control relay ci-RHD for the opposing signal at the left hand ender the passing siding. Relay lRl-ID releases .andby opening its contact I !2 cuts off the supply of alternating current from therails of sections 3' IJand ill of the stretch .ofmain track adjacent the passing siding.

When the .train vacates the single track block so that relays ITR and "2TB pick :up, c.urrent is supplied over line wires 23 and 24 to the mechanism for signal .EL to =icauseit to displaya permissive indication and to establish the circuit of relay ISLPC so that it .picks up to release relay SLSR and to cause current of normal polarity to be supplied to the line wires 41! and M. This current keeps the neutral-contacts of relay QLHD icked up and moves the polar contacts of the relay to their left hand .or normal position so that if the signal ALA is again cleared for a following train, the signal will display its green or proceed indication.

When relay SLPC picks up, its front contacts I2! and I28 again establish the circuit previously traced for connecting the primary winding of transformer 6Z'I across the rails of section 5T. Accordingly the alternating current supplied over the rails of section 5T energizes the relay IiZR through the transformer BZT and the recti-. fier EZK. When contact 832 of relay 162R picks up, it establishes the circuit for the primary winding of transformer QTT, with the result that alternating current is again supplied to the rails of section AT, and through the transformer ;2-'4T'I"to the rails of section "2T.

When the train 'vacates section IT and the track relay ITR picks up, its front contacts in the circuit for relay ELI-ID again close, but relay ZLHD remains deenergized because relay 8TB is released due to the occupancy ofsection ET by the train, As a result, no alternating current is supplied to the rails of section IT at this time. since the circuit .for the primary winding of transformer i'IT remains interrupted by contact N5 of relay .ZLHD. When relay ITR picks up and energy is again supplied over the line wires '23 and 24 to the mechanism for signal 6L, relay ZLAR again becomes energized and its contact M2 in the circuit for transformer ITT is closed.

When the westbound train under discussion progresses further, and vacates section 3T of the single track block at the left, relay ZLHD will again 'be energized, and when its contact I45 picksup, energy is supplied to the primary winding of transformer ITT, and as a'result, alternat- 15 ing current is supplied to the rails of section 4'1 and through the transformer IBTT to the rails of section 8T. The system is now in'the condition originally described.

It will now be assumed that the operator at the control office desires to set up the system "for a train movement from left to right. Accordingly, control codes are set to field stations i-2 and 34 and relay ZWFSR is operated to its reverse position and relay iEFSR is operated to its normal position.

As explained above, when the traffic relays ZWFSR and QEFSR at the opposite ends of the single track stretch are positioned for westbound traffic, energy is supplied to the reversible line circuits which control the wayside signals at the west or exit end of the stretch and is cascaded or repeated to the east or entrance end of the stretch. In addition, the supply of alternating motor car indicator control current to the track rails is governed by the traffic relays ZWFSR and AEFSR in such manner that when the stretch is set up for westbound traffic, alternating current is supplied to the track rails at the east or entrance end of the stretch and is cascaded or repeated to the west or exit end of the stretch.

As hereinafter explained, when the traffic relays ZWFSR. and QEF'SR, are positioned to establish eastbound traffic in the single track stretch, energy is supplied to the reversible line circuits for governing the wayside signals at the east end, which therefore becomes the exit end, and the west end then becomes the entrance end. Similarly, when the traffic relays 2WFSR and dEFSR are positioned for eastbound traffic in the track stretch, the supply of alternating current to the rails of the stretch is transferred from the east to the west end of the stretch so as to be supplied at the new entrance end of the stretch.

In order to cause the trafiic relays ZWFSR and 4EFSR to change the signaling system from westbound to eastbound traffic, the contacts of relay 8WFSR are moved from their normal to their reverse position and the contacts of relay AEFSR are moved from their reverse to their normal position.

On movement of the contacts of relay ZWFSR to their reverse position, the supply of current to line Wires 23 and 24 is cut off and these Wires are connected to relay ZRHD. When the supply of current to wires 23 and 24 is cut off, the signal 6L goes to stop and interrupts the supply of current to relay iiLPC and it releases to cut off the supply of current to line Wires 40 and ii, and to interrupt the pick-up circuit of relay GLSR to insure that it remains released. When the supply of current to line wires at and M is cut off, the relay lLHD releases, if it is not already released because of interruption of its circuit due already because of interruption of its circuit due to movement of contacts and 5| of relay lEFSR to their normal position.

When the contacts 50 and 51 of relay AEFSR move to their normal position, current of one polarity or the other is supplied to line wires 40 and 4! through the winding of relay 4RAR. The polarity of the current supplied to wires 40 and 4! is governed by contacts of relay ARPC, which is controlled in the usual manner in accordance with the indication displayed by signal AB.

The current supplied to line wires M and iii feeds over back contacts of relays LPG and GLSR to the mechanism for signal BR, and conditions this signal to display an appropriate indication, While the contacts of the signal mechanism establish a circuit for relay GRPC and it picks up to establish a circuit for supplying current of normal polarity to line wires 23 and 25.

The current supplied to line wires 23 and 2 is supplied over reverse polar contacts 26 and 2| of relay ZWFSR to relay 2RHD and picks up its neutral contacts and moves its polar contacts to their left-hand or normal position, so as to enable current to be supplied over its contacts to the mechanism for signal ZRA when the contacts of relay ZRHSR are reversed in order to clear signal ZRA for an eastbound train movement.

When contacts of rela QEFSR, are operated to their normal position, contact I23 interrupts the circuit for the primary winding of transformer STT, and as a result the supply of alternating current from transformer ESTT to the rails of section ST is cut off. Accordingly, alternating current is no longer supplied from the rails of section 6T through the transformer 5-BTT to the rails of section ST, and as a result energy ceases to be supplied to transformer GZT, and through transformer GZT and the rectifier 62K to the indicator control relay BZR, if it has not already been cut off because of release of relay GLPC. When relay 62R releases, its contact I32 interrupts the supply of energy to the primary winding of transformer 4T'I, so that the supply of alternating current from transformer QTT to the rails of section 4T is interrupted, if it is not alread interrupted because of picking up of relay ESE-PC, and the alternating current supplied from the rails of section dT through the transformer 2-4TT to the rails of section 2T is also cut off.

Additionally, when the contacts of relay iEFSR operate to their normal position, polar contact H5 establishes a circuit including front contact I 47 of relay QRAR for supplying energy to trans former STT.

When relay SLPC releases, its contacts 12? and I28 interrupt the circuit for connecting the primary winding of transformer GZT to the rails of section ST, and establishes the circuit for connecting the secondary winding of transformer 5TT to the rails of section 5T.

When signal 5R clears, the relay BRPC is energized and its contacts pick up, and its contacts I 36 and 39 disconnect the secondary winding, of transformer ATT from the rails of section GT, and connect the rails of section 5T to the primary winding of transformer tZT.

When relay ZWFSR reverses, its contact M0 establishes the circuit for the primary winding of transformer 2TT, which circuit is traced from terminal BX, over front contact N8 of relay BTR, front contact 149 of relay 2TR, front contact of relay ZRRGP in multiple with front contact 152 of relay ZLHD and correspondence contact I50, reverse polar contact I46 of relay ZWFSR, over front contact I53 Of track relay ITR, and through the primary winding of transformer 2TT to terminal CX. As a result, alternating current is supplied to the rails of section 2T and through the windings of transformer 2-4TT to the rails of section 4'1 and over the rails of section 4T to the primar winding of transformer BZT. The energy supplied to the primary winding of transformer EZT induces alternating current in the secondary winding of the transformer which is rectified by the full-wave rectifier BZK, and is supplied to the winding of the indicator control relay BZR. When relay GZR picks up, it

establishes a circuit including back contact 13; of relay BLPC for the primary winding of transformer TT. As a result, alternating current is supplied to the rails of section ET and through the windings of transformer 5-6TT to the rails of section As previously explained, the supply of energy to the primary winding of transformer STT is cut off by polar contact I23 of relay GEFSR which now occupie its normal position.

When trafiic relay ZWFSR reverses its contacts, the supply of current to the winding of relay ZLAR is interrupted and relay ZLAR releases so that its front contact I42 interrupts the circuit for the primary winding of trans-'- i'ormer ITT.

It will be apparent that alternating current is now supplied at the entrance end of the single track stretch, and is cascaded from the'west or entrance end of the stretch to the east, or the exit end of the stretch, in a manner similar to that originally described for westbound traflic, so that alternating current is supplied to each section in the stretch.

Although the supply of alternating current is interrupted for a short time while the direction of traffic is being changed, this interval is usually short enough so that the motor car operator is not likelyto remove the car from the'track before the alternating currentis again supplied to the rails. I

The operation of the equipment when the eastbound signals ZRA or ZRB are cleared, and when an east-bound train moves into and through the stretch is similar to that described above for the westbound direction, and a detailed description of the operation under such circumstances is considered unnecessary.

From the foregoing it will be seen that my invention provides means for at times supplying alternating current to the rails of each section on a stretch of single track railway through which trafiic may move in either direction. The alternating current is supplied to the section atthe entrance end of the stretch and is cascaded through the track sections to the exit end of the stretch. When a train approaches and the signal authorizes entrance of the train into the stretch, and when the train moves through the stretch, the supply of alternating current is cut off at the entrance end of the stretch, and, con- &

sequently, is cut oil throughout the stretch and remains out off in advance of the train as the train moves through the. stretch. Alternating current is again supplied to the sections in the rear of the train after the train has advanced a predetermined distance from the section.

Additionally, alternating current is supplied to the rails of the sections of main track adjacent the passing siding during the time that the signals governing the entrance of trains into these sections are at stop and no train is occupying any of the sections. When a train is authorized to proceed through thesev sections, the alternating currentis cutoff from the rails ahead of the train andafter the train has vacated the sections, alternating current is again supplied to the rails of the sections in the rear of the train.

Accordingly, it will be apparent. thatmotor cars equipped with apparatus responsive to the presence or absence of alternating current in the rails over which the motor cars operate will be provided with information as to traffic conditions in the stretch, so that on the approach of a train authorized to enter the stretch the operators of the cars are'warned in ample time to remove the car from the track.

Referring to Figs. 2A, 2B andZC of the drawings, there is shown a modification of my invention which I may employ. The wayside signaling circuits are substantially the same as shown in Figs. 1A, 1B and 1C and a detailed explanation of their arrangement and operation is not considered necessary.

Each of the track sections in Figs. 2A, 2B and 2C is provided with a track transformer TT having its secondary winding connected across the rails at the track relay end of the section, and the track battery TB located at the other end of the section has a reactor in series therewith tolimit the flow of alternating current through'the battery. 7

In" addition, a supplementary two-wire line circuit is provided, which extends the length of the single track stretch. This supplementary line circuit is governed by the traffic relays ZWFSR and 4EFSR at the opposite ends of the stretch in such a manner that it is supplied with energy at the entrance end, in accordance with the direction of traffic established, by these relays.

Furthermore, as hereinafter explained, the supply of energy to the supplementary line circuit is also governed by traffic conditions in the track stretch approaching the'ends of the single track stretch with which the line circuit is associated.

Indicator control relays are connected across the supplementary line circuit at locationsv where it is desired to supply alternating current to the track sections'in the single track stretch. The supplementary line circuit for the indicator control relays is carried over front contacts of each of the track relays for the track sections in then J trance of trafilc into these track sections.

The system of Figs. 2A, 2B and 2C is shown in the condition which it assumes when the track stretch is vacant, the head block signals are all at stop, and the reversible signal circuits. are set up as required for westbound trafilc.

At this time current is supplied to the line wires I51 and [5B of the supplementary line circuit at the east end of the stretch, where contact Ifiil of traffic relay :iEFSR, Fig. 2C is reversed to connect the supplementary line wire l5! to terminal B of the local source of current over front contact M52 ofv relay lLRGP and front contact ltfiofrelay ARI-ID in multiple,

and line wire H58 is connected to terminal C of this source at contact I88 of relay 3TB. Since all of the track relays are picked up, it will be apparent from the drawings that each of the indicator control relays ZWKR, ZEKR, BKR, EWKR, and QEKR are energized at this time.

- The primary winding of transformer lTT, Fig.

2A, is supplied with energy over a circuit extending to terminal BX of an alternating current source at front contact H of relay ZWKR, and the primary winding of transformer HT is supplied with energy over a circuit extending toterrninal BX at front contact l6! of relay 2EKR. The primary windings of transformers lTT and 5TT are supplied with energy over circuits including front contacts I69 and I12 of relays {iIR and 5TB, respectively, which extend ga es to terminal BX at front contact I of relay GKR. The primary winding of transformer 6'IT is supplied with energy at this time over a connection to terminal BX at front contact I14 of relay 4WKR, and the primary winding of transformer 3TT is connected to terminal BX at front contact N5 of relay IEKR. In addition, the primary winding of transformer ITT is supplied with energy over a circuit including front contact I'II of relay IRHD and extending to terminal BX over front contact I'IB of relay lLl-ED in multiple with a normal polar contact I19 of relay GRHSR, and the primary winding of transformer 8TT is supplied with energy over a circuit including front contact I8I of relay 2Ll-lID extending to terminal BX over front contact I82 of relay ZRHD in multiple with a normal polar contact I83 of relay ZLHSR.

Accordingly, it will be apparent that at the time, alternating current is supplied to the rails of each of the track sections in the single track stretch and in the main track stretch adjoining the passing sidings so that a motor car moving through the stretch at this time will receive alternating current from the rails of each section, thereby indicating that it is safe for the car to be operated in the stretch.

It is now assumed that the operator desires to clear the westbound head block signal 4LA to authorize an approaching westbound train to move through the stretch from right to left' Accordingly, a control code is sent from the ofiice to field station 34 to reverse relay QLHSR. When signal lLA clears, the circuit for relay 4LRGP is interrupted, and its contact I52 opens, V

but current continues to be supplied to the supplementary line Wires I5! and I58 over front contact I63 of relay GRI-ID. When the train approaches within the control limits of relay IRl-ID, and enters section IT, as shown by placing Fig. 2A at the right of Fig. 2C, or when the supply of energy to relay fiRl-ID is cut off as a result of clearing the westbound entering signal 2L, relay dRHD releases and its front contact I'II interrupts the supply of energy to the primary winding of transformer ITI, and as a result, the supply of alternating current to section IT is cut off.

In addition, when relay IRHD releases its front contact I63 interrupts the supply of energy to supplemental line wires I51 and I58, and the indicator control relays ZWKR, 2EKR, BKR, IWKR, and EKR are deenergized and their contacts release, thereby interrupting the supply of alternating current to the rails of sections IT, 2T, 3T, 4T, ST and GT.

It will be apparent that a motor car moving over any of these sections will receive no alternating current at this time, thus indicating the approach of a train.

When the westbound train passes signal 4LA and enters section 3T, track relay 3TB releases, and as a result, signal ALA is restored to stop and the contacts of the signal control relay GLHSR are restored to normal. When signal MA is restored to stop, the circuit for relay ALRGP is established and relay 4LRGP picks up. Contact I62 of relay ALRGP is again closed, but since the contacts of track relay 3TB are released, no energy is supplied over the supplemental line circuit to the indicator control relays and they remain released.

When the train advances into sections 6'1 and ET, relays BTR and 5'IR release and further in- 20 terrupt the supply of energy to the supplemental line wires I57 and I58.

When the train vacates section 3T, relay 3TB picks up, and relay 4RHD is again energized. When relay GRHD picks up, energy is supplied to the primary winding of transformer 'ITT by the circuit which includes front contact I'II of relay :IRHD and normal polar contact I19 of relay IRHSR, so that alternating current is again supplied to the rails of section IT in the rear of the westbound train.

At this time, that is to say, when relay 3TB picks up, a circuit is established for energizing relay AEKR extending from terminal B at reverse polar contact I60 of relay IEFSR, over front contact I62 of relay 4LRGP, and front contact I63 of relay 4RHD in multiple, over front contact I85 of relay 3TB through the winding of relay IEKR to terminal C. When relay 4EKR picks up, its contact I'l5 completes the circuit for the primary winding of transformer 3TT so that alternating current is now supplied to the rails of section 3T.

Although when relay 3TB, picks up connections are established for supplying energy to the right hand or east end of the supplementary line wires I51 and I58, the circuits which include these wires are interrupted, by contacts of the track relays of the occupied track sections so as to prevent the supply of energy to the indicator control relays'governing the supply of alternating current to the rails of the sections occupied by the train or in advance of the train. Accordingly, the supply of alternating current to the occupied sections and to the sections in advance of the train continues to be interrupted so that the indication means on a motor car present in one of these sections will display a danger indication.

When the train advances into sections 4T and 2T, relays IITR and, 2TB. release to further interrupt the circuits which include the line wires I51 and I58.

When the train vacates section 6T, relay GTR picks up and energy is supplied to relay IWKR over a branch of the circuit for relay lEKR which includes front contact I85 of relay 3TB, the winding of relay 4WKR, front contact I8'I of relay GTR, and extends to terminal C at front contact I88 of relay 3TR. When relay 4WKR picks up, its front contact I14 completes the circuit for the primary winding of transformer BTT, so that alternating current is supplied to the rails of section 6T.

As pointed out above, the contacts of the track relays of the occupied sections prevent the supply of energy over the supplementary line circuit to the other indicator control relays and they remain released to prevent the supply of alternating current to the associated sections.

When the train vacates section 5T, relay 5TB picks up, and energy is again supplied over the supplementary line wires I51 and I58 to relay BKR. Additionally, front contact I72 of relay 5TB is closed so that alternating current is again supplied over front contact I of relay BKR to the primary winding of transformer 5TT, and as a result, alternating current is supplied to the rails of section 5T.

Although front contact I'IB of relay BKR is picked up, energy is not supplied to the primary winding of transformer 4TT since contact I59 of relay ITR remains released as long as the train occupies section 4T.

If signal 2L is now cleared to permit the train to leave the single track stretch, relay ZLI-ISR,

posing signal control relay at the other end of the passing siding, corresponding to relay iRI-ID as shown by placing Fig. 20 at the left of Fig. 2A, thus cutting off the supply of alternating current from the rails of section T1 in the stretch of main track adjacent the passing siding.

When the train passes signal 2L, track relay ITR. releases and relay 2LHS'R is restored to its normal position. However, the contacts of relay ITR now interrupt the circuit for relay ZLHD and its contact ISi releases to further interrupt the circuit for the primary winding of transformer aTT, so that the supply of alternating current to the rails of section 8T continues to be interrupted.

Additionally, when relay ITR releases, its front contact iQl further interrupts the supply of energy over the supplementary line circuit to relay ZWKR, with the result that relay ZWKR r mains released and prevents the supply of alternating current to the rails of section IT.

Whenthe rear of the train vacates section 4T, contact l69 of relay @TR picks up, and since contact 110 of relay SKR is picked up, energy is now supplied to the primary winding of transformer llTT with the result that alternating current is again supplied to the rails of section 4T. When the rear of, the train vacates section 2T, track relay ZTR picks up, and its contacts I93 and I84 again establish the connection between relay ZEKR and the supplementary line wires I51 and I58, so that energy is supplied to the winding of relay ZEKR. Accordingly, its contact I61 picks up with the result that energy is again supplied to the primary winding of transformer 2TT so that alternating current is supplied to the rails of section 2T.

When the train vacates section lT, track relay ITR. picks up and its front contact l9! again establishes the connection between the supplementary line wires I51 and 158 and the winding of relay ZWKR, so that relay ZWKR, is energized.

When contact [65 of relay 2WKR picks up, energy is again supplied to the primary winding of transformer iTT and as a result, alternating current is again supplied to the rails of section IT.

When the train advances beyond the control limits of relay 2LI-ID, relay .ZLI-ID will be energized and its neutral contact l8! will again establish the circuit for the primary winding of transformer BTT and as a result alternating current will be supplied to the rails of sectionBT.

The system is now restored. to the condition originally described. Since the circuits are symmetrical, the operation of the equipment for a movement of an eastbound train through the stretch is similar to that described above for a westbound train movement and a detailed explanation is considered unnecessary.

From the foregoing it will be apparent that the arrangement of apparatus embodying my invention as shown in Figs. 2A, 2B and 2C operates so that alternating current is normally supplied to the rails of each section in thesingle track stretch and in the main track portions beside the passing sidings, and that the alternating current is cut off from the rails of each section section. Accordingly, on the approach of a train authorized to enter a stretch, the operators of motor cars moving through the stretch will be warned in ample time to remove the car from the rails and the supplementary signaling system also provides protection for following moves made by motor cars after the train has passed.

On the other hand, the approach of a train not authorized to enter a stretch does not interfere with the supply of alternating current to the rails of the stretch and hence does not cause the in dication means on a motor car'in the stretch to display its warning indication. This insures that trains will not interfere with operation of the motor cars unless the trains are a hazard to the motor cars.

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

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

1. In a supplemental signalling system for governing indicators on special. railway vehicles having insulated wheels and provided with indication means responsive to control current supplied to the rails over which the vehicle operates, the combination comprising a stretch of railway track through which traffic at times moves in aselected direction,the rails of said track stretch being divided into a plurality of track sections, each of said track sections being provided with a track circuit including a source of. current and a track relay responsive thereto but not to said control current, a control circuit comprising a line circuit extending the length of the stretch and having in series therewith front contacts of said track relays, means governed by traffic conditions adjacent the entrance end of said stretch for supplying energy to said control circuit at the entrance end of said stretch, and means responsive to energy supplied over said line circuit for supplying said control current to the rails of each of said sections.

In a supplemental signaling system for' a stretch of railway track through which special vehicles having insulated wheels are operated at times, said special vehicles being-equipped with indication means responsive to the flow of cur-- rent of a distinctive character in the track rails, said track stretch being divided into a plurality of successive track sections each or" which is provided with a track circuit for detecting the pros ence of a train therein comprising a source of current connected across the rails of the section at one end and a track relay responsive thereto connected across the rails at the other end, said track stretch being provided with a principal sig naling system comprising a system of reversible circuits governed by said track relays and by.

other as designated by said trafi'ic governing means, said supplemental signaling system comprising a line'circuit extending the length of the stretch and having in series therewith front contacts of said track relays, means governed by traffic conditions adjacent the entering end of said stretch and by said traffic governing means for supplying energy to said control circuit at the designated entrance end of said stretch, and means for each of said track sections responsive to energy supplied over said line circuit for supplying current of said distinctive character to the rails of such section for the control of the indication means on a special vehicle in such section.

3. In a supplemental signaling system for a stretch of railway track through which special vehicles having insulated wheels are operated at times, said special vehicles being equipped with indication means responsive to current of a distinctive character in the track rails, said track stretch being divided into a plurality of track sections and provided with a principal signaling system for the control of train movements including a signal at each end of the stretch and a system of reversible circuits extending the length of said track stretch for controlling said signals in accordance with traffic conditions in said stretch, said principal signaling system also including trafllc control means at the ends of said stretch manually governed from a central office to condition said system of reversible circuits to prepare said stretch for traffic in one direction or the other and thereby permit clearing of the signal at the corresponding entrance end of the stretch, and having signal control means at each end of said stretch manually controlled from said office effective normally to hold the associated signal at stop and to clear the associated signal only when said system of reversible circuits has prepared the stretch for traffic in the direction in which said signal is at the entrance end of the stretch, said supplemental signaling system comprising supplemental control means at each end of said stretch for supplying current of said distinctive character to the rails of each section in the stretch, means governed by the traffic control means at each end of the stretch for controlling the associated supplemental control means so that said current of distinctive character is supplied to the rails at the entrance end of the stretch, and means governed by the signal control means at each end of the stretch for controlling the associated supplemental control means so that it is rendered ineffective to supply said current of distinctive character when said signal control means is operated to clear the associated signal.

4. In a supplemental signaling system for a stretch of railway track through which special vehicles having insulated wheels are operated at times, said special vehicles being equipped with indication means responsive to the presence of current of a distinctive character in the track rails, said track stretch being divided into a plurality of track sections and provided with a principal signaling system including a signal for the control of train movements at each end of the stretch and a system of reversible circuits extending the length of said track stretch for controlling said signals in accordance with traffic conditions in said stretch, said principal signaling system also including traflic control means at the ends of said stretch manually governed from a central ofiice to condition said system of reversible circuits to prepare said stretch for traffic in one direction or the other and thereby permit clearing of the signal at the correspond ing entrance end of the stretch, and having signal control means at each end of said stretch manually controlled from said oifice effective normally to hold the associated signal at stop and to clear the associated signal only when said system of reversible circuits has prepared the stretch for traffic in the direction in which said signal is at the entrance end of the stretch, said supplemental signaling system comprising supplemental control means at each end of said stretch for supplying said current of distinctive character to the rails of each section in the stretch, means for governing each supplemental control means so that it is eiiective to supply said current of distinctive character to the rails only when the associated traffic control means designates the end of the stretch at which such supplemental control means is located as the entrance end of the stretch and so that each supplemental control means is rendered ineffective when the associated signal control means is operated to clear the signal governed thereby.

5. In a supplemental signaling system for a stretch of railway track through which special vehicles having insulated wheels are operated at times, said special vehicles being equipped with indication means responsive to the presence of alternating current in the track rails, said track stretch being divided into a plurality of track sections and provided with a principal signaling system including a signal for the control of train movements at each end of the stretch and a system of reversible circuits extending the length of said track stretch for controlling said signals in accordance with trafilc conditions in said stretch, said principal signaling system also including trafiic control means at the ends of said stretch manually governed from a central office to condition said system of reversible circuits to prepare said stretch for traffic in one direction or the other and thereby permit clearing of the signal at the corresponding entrance end of the stretch, and having signal control means at each end of said stretch manually controlled from said oiiice which normall holds the associated signal at stop and is effective to clear the associated signal only when said system of reversible circuits has prepared the stretch for traffic in the direction in which said signal is at the entrance end of the stretch, said supplemental signaling system comprising supplemental control means at each end of said stretch for supplying alternating current to the rails of each section in the stretch, means for rendering each supplemental control means effective to supply said alternating current to the track rails when the associated traflic control means designates that direction for train movements for which said supplemental control means is at the entrance end of the stretch, provided either that the associated entering signal is held at stop by its signal control means or an approach section of track adjoining said entrance end of the stretch is not occupied by a train.

6. In a supplemental signaling system for a stretch of railway track through which special vehicles having insulated wheels are operated at times, said special vehicles being equipped with indication means responsive to alternating current in the track rails, said track stretch being divided into a plurality of track sections and provided with a principal signaling system ineluding a signal at each end of the stretch for the control of train movements and a system of reversible circuits extending the length of said track stretch for controlling said signals in accordance with trafilc conditions in said stretch, said principal signaling system also including trafiic control means at the ends of said stretch manually governed from a central office to condition said system of reversible circuits to prepare said stretch for trafiic in one direction or the other and thereby permit clearing of the signal at the corresponding entrance end of the stretch, and having signal control means at each end of said stretch manually controlled from said office which normally holds the associated signal at stop and is effective to clear the associated signal only when said system of reversible circuits has prepared the stretch for trafiic in the direction in which said signal is at the entrance end of the stretch, said supplemental signaling system comprising supplemental control means at each end of said stretch for supplying alternating current to the rails of each section in the stretch, means for rendering each supplemental control means effective to supply said alternating current to the track rails when the associated trafiic control means designates traffic in the direction in which said supplemental control means is at the entrance end of the stretch, and means responsive to the presence of an approaching train within a predetermined distance at the end of the stretch at which said supplemental control means is efiective for discontinuing the supply of alternating current to the rails of the stretch provided the entering signal has been cleared to authorize said train to enter the stretch.

7. In a supplemental signaling system for a stretch of railway track through which special vehicles having insulated wheels are operated at times, said special vehicles being equipped with indication means responsive to the presence of current of a distinctive character in the track rails, said track stretch being divided into a plurality of track sections each of which is provided with a track circuit including a track relay for detecting the presence of a train therein, said track stretch having a railway signal at one end for governing the movement of trains into said stretch, and having signal control means governed by said track relays for controlling said signal in accordance with traffic conditions in said stretch, said supplemental signaling system comprising a line circuit extending the length of said stretch which includes front contacts of the track relay for each track section in said stretch, means for each of said sections responsive to energy supplied over said line circuit for supplying said current of distinctive character to the rails of such section, and means governed by said signal control means for supplying energy to said line circuit at the end adjacent said signal.

8. In a supplemental signaling system for a stretch of railway track through which special vehicles having insulated wheels are operated at times, said special vehicles being equipped with indication means responsive to the presence of current of a distinctive character in the track rails, said track stretch being divided into a plurality of track sections each of which is provided with a track circuit including a track relay for detecting the presence of a train therein, said track stretch having a railway signal at one end for governing the movement of trains into said stretch and having means governed by the track relays for controlling said signal in accordance with trafiic conditions in said stretch, said supplemental signaling system comprising a line circuit extending the length of said stretch which includes front contacts of the track relay for each track section in said stretch, means for each of said sections responsive to energy sup-plied over said line circuit for supplying said current of distinctive character to the rails of such section, means governed by said signal for supplying energy to said line circuit at the end adjacent said signal when said signal stands at stop, and means governed by occupany of a portion of the track adjoining said track stretch and constituting an approach zone for said signal for also supplying energy to said line circuit when, said signal is cleared provided said approach zone is not occupied by a train.

WILBUR V. GRO'SJEAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,344,333 Van Horn Mar. 14,1944 2,390,010. Talbert et al Nov. 27, 1945 2,410,504 Judge Nov. 5, 1946

Images