US2389982A - Coded railway signaling system - Google Patents

Description

A. L. JEROME 2,389,982 GODED RAILWAY szemuuq SYSTEM F iled March 2, 1944 7 Sheets-Sheet 1 Eeofzfip I Unif.

43W fig 114.

v INVENTOR 9 Ari/ ap fer'ome Hff ATTORNE Y Nov. 27,1945. A. JEROME 2,339,932 I CODED RAILWAY SIGNALING SYSTEM Fiied March 2, 1944 7 Sheets-Sheet 2 1 IgWIH 45' 59 l I l I v 55W 0 fig. 5.

INVENTOR Ari/2a! Z Jepame;

I Q a M HI! ATTORNEY Nov.

A. L. JEROME 2,389,982

CODED RAILWAY SIGNALING SYSTEM WWW iled March 2, 1944 7 Sheet-Sheet a 6 1 5W5 amp f I 5 (I I 1095 1;! L L 77 a @X J 79 1;; 6X Q .7. Turned La AlzePnafon Q'ZMIQJL HIT ATTORNEY Nov. 27, 1945. A. L. JEROME 2,389,982

CODED RAILWAY SIGNALING sxsmm Filed March 2, 1944 7 Sheets-Sheet 4 (X' 169 wx" HIT ATTORNEY W A. l... JEROME CQDED RAILWAY SIGNALING SYSTEM '7 Sheets-Sheet 5 Filed March 2, 1944 INVENTOR BY Ami 2UP Z k/kpome a f H13 ATTORNEY NEW. I A, L JEROME CODED RA ILWAY SIGNALING SYSTEM Filed March 2, 194 7 Sheets-Sheet 7' INVENTOR Alffillf' Z. Jepame @if N H11! ATTORNEY the section rails,

, Patented Nov. 27, 1945 CODED RAILWAY SIGNALING SYSTEDI Arthur L. Jerome, Edgewood, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application March 2, 1944, Serial Nol' 524,708

11 Claims.

. My invention relates to coded railway traffic controlling apparatus.

In application for Letters Patent of the United States, Serial No. 412,279 of James J. Van Horn,

' now Patent No. 2,344,333, granted March 14, 1944,

there is shown a signaling system for use'on stretches of single track over which traflic may move in either direction. In the system of the Van Horn application'each track section is provided with two track circuits, one for each direction of trafllc, while the system operates so that when trafllc is established for either direction coded energy is supplied to the rails of each track section at the. exit end thereof and operates the track circuit apparatus for that direction of traiflc to control the wayside signals. The system of the Van Horn application is also arranged so that on movement of a train through the track stretch steady. energy may be supplied to the stretch at the entrance end thereof and operates the apparatus of the track circuits for the other directionof traflic to cause the steady energy to be cascaded through the stretch to the exit end of the stretch to discontinue the supply of coded energy to the stretch when the stretch is vacated.

In some situations, it is desirable to provide means for indicating at the exit end of each section when that section is occupied. This means may'be employed for any appropriate purpose as, for example, to control the supply of energy to th lamps of the wayside signal for the adjae cent track section in advance, or to control the supply of coded alternating current cab signal control energy to the section rails.

It has heretofore been proposed to govern approach control means by feed-back energy supplied to the rails of a track section in the intervals between impulses of master code supplied over It is an object of this invention to provide. for each track circuit of a track section having two track circuits, one for each direction of traflic,

approach control facilities governed by feed-back energy.

Another object of the invention is to provide in a signalirig system of the type shown in the Van Horn application, approach control facilities operated by feed-back energy for each direction .of trafllc in each track section.

A further object of this invention isto provide a system of the type described which is arrangedv so that the approach control facilities for either direction of tramc are not operative until that direction of tramc has been established.

Another object of the invention is to provide for a track section track circuit apparatus of the type described which is arranged so that neither master code nor feed-back energy employed in.

the track circuit for one direction of trailic will I interfere with the track circuit apparatus for the other direction of traflic.

A further object of the invention is to provide for a track section track circuit apparatus of the type described which is arranged so that the track circuit apparatus for either direction of traflic will not be improperly operated by energy stored in the section rails as a result of the supply to the sectionrails of master code or feed-back energy to the track circuit for either direction of traflic. Another object of the invention is to provide coded track circuit apparatus of the type described which is arranged so that one approach control relay serves for one track section when trailic is established for one direction and serves for the adjoining track section when trafiic is established for the other direction of traflic.

A further object of the invention is to provide a system of the type described which incorporates means for energizing the approach control relays when neither direction of traflic is established in, the track stretch. Another object ofthe invention is to provide apparatus of the type described and arranged to reduce or eliminate establishment of the approach controlled circuits on a change in the established direction of trafiic in the track stretch.

A further object of the invention is to provide 7 for use in .a system of the type described front 35 and back contact coding cut-section apparatus." Anotherobject of the inventionv is to provide for use in a system of the type described equipment for use at a highway crossing to control the crossing signals and to also control the supply of coded cab signal control energy to the approach sections to the highway intersection.

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

I shall describe one form of apparatus embodying my invention together with modifications thereof which I may employ, and shall then point out the novel features thereof in claims.

-Similar. reference -.characters refer to similar parts in each of the several views.

In the drawings,

Figs. 1A and 1B,' when placed together with Fig. 13 at the right, form a diagram of a track 55 section and the adjacent ends of th two adioin ing track sections equipped with signalin'gappaf ratus embodying my invention;

Fig. 2 is a fragmentary diagram showing means which may be employed in place of that" shown in Fig. 1;

Fig. 3 is a diagram showing apparatus which may be employed at a cut-section where back contact coding is employed;

Fig. 4 is a diagram showing apparatus which may be employed at a cut-section where'iront contact coding is employed; and

Figs. 5A and 513,. when placed together with Fig. 5B at the right, form a diagram of apparatus which may be employed at a highway intersecs tion.

Referring to Figs. 1A and 1B of the drawings, there is shown a stretch of railway track having track rails l and 2 which are divided by insulated joints 3- into track sections for signaling purposes. One complete track section designated ST, and portions of the adjacent ends of the adjoining track sections designated 4T and BT, are shown. For purposes of illustration it will be assumed that the right-hand end of the track stretch is east and that the left-hand end of the stretch is west so that train movements from left to right are eastbound while train movements from right to left are westbound.

The track stretch is'equipped with coded signaling apparatus of the type shown in the above 80 identified application of James J. Van Horn, while the track circuits have been modified to provide for the supply of feed-back energy over the section rails to control energization of approach control relays which govern the supply of coded alternating current cab signal control energy to the section rails, and to also control the supply of energy to the lamps of the wayside signals.

The construction and operation of the locomotive cab signal apparatus governed by the coded alternating current supplied to the track rails is not a part of this invention and this equipment may be constructed as shown-in Letters Patent of the United States No. 1,986,679, issued Janumy 1, 1935, to Lloyd V. Lewis.

The alternating current supplied to the section rails may be suppliedfrom a commercial source and may be distributed throughout the track stretch by a transmission line, not shown,

.while the terminals of this source are designated BX and CX in the drawings.

- Each signal location is provided with a source of direct current, such as a storage battery not shown, the terminals of which are designated B andCin the drawings. I

.As explained in the Van Horn application; when the track stretch is conditioned for eastbound traflic, coded ener y is, supplied at the east end of thetrack stretch and is cascaded through the various track sections to the west end of the stretch to cause a signal at that point to display a permissive indication. Similarly,

when the track stretch is conditioned for westbound traflic, coded energy is supplied at the west end of the track stretch and is cascaded through thevarious track sections to the east end of the stretch to cause the signal at that point to display a permissive indication. In addition.

on movement of a train throughthe track stretch in either direction steady energy may be'supplied to the stretch and is cascaded through the stretch behind the train to out ofl the supply of coded energy over the rails of the-various track-sec- 76 :ase aesa xtions-and to indicate at the exit end of the sectlon when the stretch is vacated.

The equipment is shown in Figs. 1A and 1B in the condition which it assumes when the stretch is vacant and is conditioned for eastbound trafflc.

' At this time, energy of code frequency issupplied to the rails of section 6T afthe righta hand orexit end thereof. As explained in con nection with section 6T, this energy is supplied from a track battery and is of such polarity that the positive terminal of the battery is connected to the lower rail 2. This energy feeds fromtrack rail 2 over back contact if] of coding relay SWCTM, winding of track relay GETR from left to right, back contact ii of relay GEIR, track winding l2 of relay GWFB, and back contact l4 of coding relay BECTM to track rail I. This energy picks up the contact of track relay SE'R. while it moves the contact of polar stick relay GWFB to its left-hand or normal position.

The track relays are all of the polar biased neutral type the contacts of which become picked up when and only when energy flows through the relay winding in a particular direction, while each of these relays is arranged so that its contact is picked up on flow of energy through the relay winding in the direction indicated by the arrow on the relay.

The feed-back detector relays F3 are of the polar stick type, the contacts of which are moved to one position by energy of one polarity and are moved to their other position by energy of the other polarity, while the contacts of these relays when moved to either position remain in that position until energy of the polarity effective to move the relay contact to its other position is supplied to the relay.

The circuits for supplying energy to the rails of a section from the track and teed-back batteries at an end of the section are arranged so thatthe positive terminal oi. one of these batteries is connected to one track rail and the positive terminal of the other battery is connected to the other track rail. Accordingly, energy of one polarity is supplied to the section rails from one battery and energ of the other polarity is supplied to the section rails from the other battery and to identify the polarity of the energy intended these have been designated normaland reverse polarity.-

Similarly, at each end of each section there are two track relays, one of which responds to energy or one polarit supplied over the track 5 rails; that is,. to energy supplied when the positive terminal of the source is connected to one track rail, while the otherrelay responds to energy of the other polarity supplied over the track rails, that is, to energy supplied when the positive terminal oi the source is connected to the other track rail, and to identify the polarity of the energy intendedthese have been designated normal and reverse polarity.

The terms normal and reverse polarity are purely arbitrary designations and either track rail may be connected to the positive terminal of the source to provide energy of normal polarity, but the batteries and track relaysat both ends of a section must be arranged in thecorrect relationship to each other.

On picking up of relay BEI'R energy is supplied over its front contact ll to slow releasin relay GEFSA, while on release .oi'relay OETR energy is supplied over back contact I! of relay BEIR, front contact of relay BEFSA,;and back picked up and its contact 20 establishes the circuit for. supplying energy to the primary wind-- ing of decoding transformer CDT so that on coding operation of relay BTM energy is induced in' the transformer secondary windings, Energy from one of these secondary windings is rectified by a contact of relay TM, as explained in Letters Patent of the United States No. 2,237,788, issued April 8, 1941, to Frank H. Nicholson and Leslie R. Allison, and is supplied to'slow release relay 6H, while energy from the other secondary winding is supplied through a resonant rectifier unit ISIIDU to relay SJ. As relays 6H and SJ are picked up, energy may be supplied over front contact 22 of relay 6H and front contact 23 of relay 1 SJ to the green lamp G of signal SSE, However, as hereinafter'explained, as long as section ST is vacant, relay SFBP is picked up and its contact 24 interrupts the circuit of the lamps of signal SSE,

On continued code following operation of track rela GETR, energy is supplied to relay SEFSA each time the track relay picks up, while each time the track relay releases, energy is supplied to relay STM and it picks up to supply energy to relay SBSA. The relays FSA and BSA are of a type the contacts of which are slow to release so that the contacts of these relays remain picked up in the periods during which the supply of energy to the relays is interrupted. Similarly, the relay 611 is of a ype the contacts of which are slowlto release so that its contacts remain picked up in the intervals between energy impulses supplied from'the decoding transformer.

On release, of the contact of the track relay GETR, energy is supplied to relay OTM and its contacts pick up, The relay STM does not pick up instantaneously and in-the period from re lease of track relay SETR until picking up of relay GTM, energy is supplied to relay BEIR over back contact ii of the track relayjETR, front contact t6 of relay SEFSA, back contact I! of relay SWFSA, asymmetric unit 52, back contact 53 of relay BTM, front contact 54 of relay 6H, frontcontact $6 of relay GEFSA, back contact 51 of relay BWFSA, and back contact 59 of relay BWCTM, The energy supplied to relay SEIR picks up its contact ll so that energy is supplied from batter SEBB to the rails of section ST. The energy from the battery GEBB flows from the positive terminal of the battery over front contact llof relay SE13, through the winding of track relay GE'I'R from right to left, and over back contact In of relay SWC'IM to track rail 2, while the negative terminal of this battery is connected over back contact I l of relay'BWCTM to track rail I. The energy supplied from battery UEBB flows through the winding of the track relay tE'I'R in the wrong direction to pick up the relay contact while, as explained in connection with section ET, the energy supplied from battery EBB to the rails of section 6T feeds to the BI is connected from the energizing circuit for relay EIR to terminal O. .The resistors 80 and BI provide snubblng circuits for the relay SEIR, and' on interruption of the circuit of the relay, delay release of the relay contacts for a period long enough to insure that feed-back energ will be supplied to the rails of section 6T for a period sufficient to operate the feed-back detector relay, but short enough'to insure thatthe relay BEIR will release before the start of the next "on period in the code supplied to section GT,

On release of relay SEIR, the supply of energy from battery EBB to the rails of section GT is cut off and relays BETR and GWFB are connected in series across the rails of section 6T. Because of the inductance of'the track-circuit of section 6T,-.on interruption of the circuit of the battery GEBB energy may continue to flow in the track circuit in the same direction as it was flowing when energy was supplied from the battery to the track circuit. If this energy continues to flow after contact ll becomes released, energy GWFB from right to left back contact I l of relay BEIR, winding of relay SETR, and back contact ID of relay GWCTM to rail 2. This energy is ineffective to pick up the contact of relay GETR,

while it may move the contact of relay SWFB to its right-hand or reverse position, but this is not objectionable sincethe circuit controlled by the contact of relay GWFB is open at front contact 63 of relay GWS. The arrangement of the track circuit is such that neither the supply of feedback energy to the section rails nor energy stored in the track circuit as a result of the'sup'ply of feed-back energy thereto will interfere with the proper operation of the track circuit apparatus.

If contact ll of relay BEIR should engage its front and back contacts simultaneously, the battery GEBB will be connected to the track winding east end of the section and operates the feedthewindingoftherelay6m,whilearesistor I2 of relay GWFB and its contact will be moved to its normal or open position, while any energy supplied to relay GETR will flow through the relay winding in the wrong direction to pick up the relay contact. Accordingly, overlapping contacts on relay GEIR cannot create a hazardous condition.

As relayBBSA is picked up, its contact 26 establishes acircuit for the code transmitter ISUCT and it operates to provide coded energy of code frequency. Energy of "75 code frequency is supplied by a continuously operating code transmitter 1501'.

At this time,'energy is supplied to the directional stick relay BES over thecircuit which includes front contact 21 of relay 6H, back contact 28 of relay SWFSA, and front contact 29 of relay BEFSA, so the contacts of. relay BES are picked up and its contact 30 interrupts the circuit of relay GWCTM and its contacts remain released to connect track relay BETR across the rails of section 6T.

The directional stick relay BWS is released at this time and energy of 180 code-frequency is supplied to coding relay SECTM over back contact 32 of relay SWFSA, a contact of code transmitter I8IICT, front contact 33 of relay 6H, and back contact 34 of relay BWS, and the relay SECTM operates at the 180 code speed. 0n pick ing up of the relay SECTM, its contacts 36 and 3] connect the track battery SETB and the secondary winding of track transformer EETT in series across the rails of section 5T with the positive terminal of the battery connected to track the track relay WTR but,

rail 2. The energy from the track battery BETB feeds over the rails of section 51 and over back contacts 39 and 40 of relay SWCTM and picks up the contact of the track relay 5ETR, while this energy also feeds over back contact 42 of relay SEIR and through the track winding 43 of relay SWFB so that the contact of this relay is moved to its left-hand or normal position.

In addition, on picking up of relay 5ECTM, its contact 45 establishes a circuit to energizethe local winding 46 of relay SEFB' and the relay 5WIR in series so that the contact 48 of relaytistor is of relatively high resistance so that it .delays release of the contact of relay 5WIR for a very short period on interruption of the circuit of the relay winding.

When relay SWIR, picks p, its contact 48 connects the feed-back batt r; SWBB in series with as the contacts of relay e ergy flows in this cir- On release of relay SECTM its 5ECTM are picked up, no cult at this time.

contact 45 interrupts the'circuit for energizing relays 5WIR and 5EFB in series and thecontact 49 of relay SEFB remains in its reverse position,

while the contact 48 of relay SWIR remains picked up for a short period because of the snubbing action of resistor 50 onthe relay winding. When contacts 36 and 31 of relay 5ECTM engage their back contacts, the battery SWBB is connected across the section rails in series with the windin of relay 5WTR, while the direction of flow of energy from the battery 5WBB through the track relay is such as to hold the relay contact released. The supply of energy from battery SWBB to relay 5WTR is cu off on release of 'relay SWIR which occurs very soon after release of the contacts of relay SECTM.

As previously explained, when relay BECTM is picked up, the track battery SETB is connected across the section rails with the positive terminal of the battery connected to rail 2. When relay 5ECTM releases, the supply of energy from the battery SE'I'B to the section rails is interrupted,

and because of the inductance of the track circuit energy may continue to flow therein in the same direction that it had been flowing. When contacts 36 and 31-01 relay 5ECTM engage their back contacts, inductive energy'from the track circuit tends to flow from rail 2 through the ballast, and through the wheels and axles of a train if the section is occupied, to rail I, thence overback yintact 31 of relay 5ECTM, through winding of elay SWTR, from right to left, front contact 48 of relay 5WIR, battery 5WBB, and back; contact 36 of relay SECTM to rail 2. This energy flows through the winding of the track relay SWTR in the proper direction to pick up the relay contact, but at this time energy from battery SWBB flows through the winding of relay SWTR, in the Op osite direction and prevents picking up of the relay contact. 1 l

Inductive energy from the track circuit, when 1 present at all, persists for only a very short .period 1 after interruption of the circuit of the track battery. The desired protection against operation of relay SWTR by this energy is obtained if relay SWIR remains picked up and maintains the supply of energy from battery SWBB through the winding of relay BWTR until the inductive discharge from the track circuit terminates, and the resistor is of such value as'to delay release of relay 5WI R for a period slightly greater than that required for inductiveenergy from the track circuit to be dissipated.

The arrangement of the track circuit apparatus is such, therefore, that energy stored in the track circuit as a result of supply of energy thereto from the track battery EETB when the stretch is conditioned for eastbound traffic will not cause improper operation of the track relay 5WTR for the track circuit which is employed when the stretch is conditioned for westbound traflic,

The coded energy supplied from battery SE'I'B to the rails of section 5T as a result of coding operation of relay EECTM feeds to relay SETR. and operates it so that relays BEFSA, SBSA, 6E8, 5H and SJ are picked up, while on each movement of the contact of track relay SETR. to its released position energy is supplied to relay SEIR during the pick-up time of relay 5TM as explained in connection with relay BEIR. Accordingly, during each off period in the master code supplied to section ET, the relay SEIR picks up and energy is supplied from the battery 5EBB to the rails of section ET. This ener y flows from the positive terminal of the battery over front contact 42 of relay SEIR, winding of relay BETR from right to left, back contact 40 of relay SWCTM, track rail 2, back contact 36 of relay SECTM, track winding of relay SEFB from left to right, back contact 48 of relay SWIR,- winding of relay SWC'IM to the'negative terminal of the battery. The energy supplied from battery 5EBB to relay 5EF'B moves the contact 49 of the relay to its left-hand or normal position so that energy is supplied-to relay 6FBP over the circuit which includes contact49, front contact 66 of relay BBB, and back contact 63 of relay 6W8. During the picked-up periods of the relay EECTM, energy is supplied to the local winding 46 of relay SEFB. as previously explained, and contact 49 is moved to its right-hand or reverse position in which, it interrupts the circuit of relay 6FBP. The relay BFBP is of a type the contacts of which are slow to release so the relay contacts remain picked up in the periods during which the supply of energy to the relay is cut off. Accordingly, contact 24 of relay BFBP interrupts the circuit of the lamps of signal SSE, while contact 68 short-circuits the primary winding of track transformer SETT over the circuit which is traced from terminal CX over front contact 69 of relays [ES and transformer primary winding to terminal CX. As a result alternating current is not supplied to the rails of section 5T at this time, while short-circuiting of the track transformer primary winding reduces arcing at the contacts of relay SEC'I'M.

At this time, energy of code frequency is supplied to relay 4ECTM over a circuit corresponding to that traced for relay SECTM so that energy of 180 code frequency is supplied to the rails of section 4T, while the equipment for section 4T operates in the same manner as that for section 5T with the result that coded energy is supplied to the adjacent section in the rear andstretch.

aaeaaea tilled above, coded energy is cascaded through the other track sections to the entrance end of the track stretch to cause the eastbound signal at that point to display a proceed indication and,

authorize an eastbound train 'toenter the track When an eastbound train enters the track stretch, the rails of the-section at the entrance end of the stretch are shunted and the signal at the entrance to the track stretch is caused to display its stop indication, while the equipment at that point may operate to supply steady energy to the west end of the stretch.

When thetrain advances into section IT, the supply of feed-back energy over the section rails is cut off and the contact 10 of relay lEF'B is not moved-to its normal position to establish the circuit of relay SFBP and the contacts of relay SFBP release so that .energy is supplied over its back contact ll, front contact I2 of relay BES, front contact 13 of relay H, and front contact 14 of relay U to the green lamp G of signal SSE. As relay 5W8 is released, its contact 18 interrupts the circuit of the lamps of signal 48W and .they remain dark. Also on release of relay SFBP its contact II interrupts the circuit short-circuiting the primary winding of track transformer lETT, while energy is supplied to this winding over the circuit'which is traced from terminal BX of the source of alternating current over back contact ll of relay EFBP, front contact 19 of relay BES, and primary winding oftransformer AETT to terminal CX of the source ofalternating current. Accordingly, on continued operation of the coding relay-IECTM, coded alternating current is supplied tofthe rails of section T to operate the cab signal apparatus on the locomotive present inthat section.

to the track transformer SETT.

When section ET. is occupied, the track relay SETR remains released and its contact 80 does not establish the circuit of relay SEFSA so its contacts release with the result that contact 8| interrupts the circuit of relay STM and its contacts remain released and relays 5H, BJ and BBSA release. on release'of relay 5H, its con'' tact I9 interrupts the circuit 'of thegreen lamp G and establishes the circuit of the red lamp R of signal SSE.

,relay BEs over its stick circuit which includes its own front contact 95 and back contact 96 of relay GEFSA so the contacts of relay 6ES remain picked up. In addition, at this time, relays SBSA, GTM, 6H and OJ release, while energy of 75 codefrequency is supplied to relay 5ECTM over the circuit which includes back contact 32 of relay SWFSA, a contact of the code transmitter 150T, front contact 99 of relay 6E5, back contact-33 of relay 6H, and back contact. 34 of relay 6W8. The relay SECTM, therefore, operates to supply energy of '75 code frequency to the rails of section 5T.

1 the adjacent section in advance and to cause alternating current cab signal control energy to be supplied to the rails of section 6T.

As explained in the Van Horn application identified above, if the equipment at the entrance end of the track stretch is operated to permit a second or following eastbound train to enter the track stretch, steady energy is not supplied to the track rails at the west .end of the stretch and coded energy continues to operate the track circuit apparatus. If, when the train under consideration vacates section 4T, steady energy is not supplied to the entrance end of. the track 40 stretch, the energy of 75 code frequency sup- On release of relaybEFSA its contact 83 interrupts the pick-up circuit for relay 5E8, while the stick circuit is established for relay SES and 111-:

' eludes back contact 84 of relay SEESA and front contact 85 of relay 5E8. The relay 5E8 is of a type the contacts of which are slow to release so contact 85 maintains the relay stick circuit during movement of the contacts of relay BES between their picked-up and released positions.

The energy supplied to relay 5E8 over its stick circuit keeps the relay contacts picked up so that contact 88 of relay IE8 continues to interrupt the circuit of relay SWCTM and contact 90 establishes the circuit including. back contact 91 plied to the rails of the section as .a result of operation of relay 4ECTM will operate the equipment at the entrance end of the section to cause the signal, not shown, at the entrance end of section 4T to display its yellow or caution indication, while energy of, code frequenc is supplied to the adjacent section in theirear; The equipment for section 4T operates at .this time in the manner explained below in connection with section 6T. c

When section ET is vacated, assuming that steady energy is not supplied at the west end of the stretch, the energy of 75 code frequency sup! plied to the section rails at the east end of the section feeds to the trackrelay 5ETR and operates it so that relay BEFSA picks up to reestablish thecircuit of. relay 5TM, while relay ETM operates so that relays 533A and; 5H pick up and relay 5J remains released. On picking up of relay SEFSA, its contact 84 interrupts the stick circuit for the relay 5E8, while on picking up of relay 5H energy is supplied to relay SES over front contact I99 of relay 5H, back contact I02 of relay WFSA, and front contact 83 of relay 'SEFSA. The relay 5ES is slow enough in releasof relay lWFSA, a contact of code transmitter 7 lamps of signal SSE.

-in'gup of relay BEFSA to picking up of-relay 5H.

-A.s relays 5E5 and 5H are picked up, energy may be supplied over front contact 1.2 of relay 5E8, front contact 13 of relay' 5H, and back contact .14 of relay SJ to the yellow lamp Y of si nal SSE,

but if section .lT is vacant, relay BFBP will be picked up to prevent supply of energ to the At this time, energy, of 180 code frequency is supplied to relay EECTM over the circuit which includes back contact 9| of relay 4WFSA, a contact of code transmitter I80CT, front contact 93 of relay, 5H, and back contact 94 of relay 5WS, while the code transmitter I80CT is operated by energy supplied over front contact 81 of relay SBSA.

When relays SEFSA and 5H pick up, the circuit for supplying impulses of energy to relay SEIR on release of the contact of relay SETR is complete and the relay SEIR operates to supply impulses of feed-back energy from battery SEBB to the rails of section 5T during the off periods in the master code supplied to the section rails. This feed-back energy operates the relay SEFB so that its contact 49 establishes the circuit of relay BFBP and it picks up so that contact 24 interrupts the circuit of the lamps of signal SSE and contact 68 cuts off the supply of energy to the primary winding of transformer SETT and short-circuits this winding.

It will be seen that when the stretch is controlled to permit following trainmovements, this track circuit apparatus operates to provide appropriate signal indications for the second train and to prevent lighting of the signals and the supply of coded alternating current to the rail of a track section until the section is occupied.

If it is not intended to permit a second train to enter the stretch, steady energy is supplied to the stretch at the entrance end thereof and is cascaded through the various sections in the manner about to be described and cuts off transmission.

of coded energy through the track stretch.

When section M is vacated, steady energy supplied to the section rails at the west or entrance end thereof feeds to relay flWTR during a released period of the contacts of relay 4ECIM so contact 92 of relay lWTR picks up and establishes the circuit of relay lWFSA so its contacts pick up with the result that contact 9| interrupts the circuit traced above for supplying energy of 75 code frequency to relay fiECTM and the contacts of relay iECTM remain released and maintain the circuit of relay 4W'I'R.

As long as section 5'1 is occupied, relay ms is maintained picked up by energy supplied over its stick circuitvwhich includes back contact 84 of relayBEFSA and front contact 85 of relay 5E5. As long as relay 5E8 is'picked up, its contact 88 interrupts the circuit of relay EWCTM and its contacts remain released with the result that track relay BETR, is connected across the rails of section ET, while energy i not supplied from track battery BWTB to the section rails.

- When section ST is vacated, codedenergy supplied from battery SETB to the section rails as a result of coding operation of relay EECTM feeds a brief time interval the contacts of relay 5E8 release so that contact 85 of relay 5ES- additionally interrupts the relay stick circuit,

5H, and back contact 84 of relay 5W8. Accordingly,- the contacts of relay lECI'M pick up and interrupt the circuit of relay 4WTR and its contact releases, but as relays 4WFSA and SEFSA are both picked up no circuit is established on release of relay 4WTR. 4

In addition, on release of relay 5ES energy is supplied to relay SWCTM over the circuit which includes front contact 9| of relay 4WFSA, back contact I05 of :relay 5W3, back contact I08 of relay 5H, and back contact 88 of relay 5E8. The contacts of relay SWCTM therefore pick up to connect the battery ,SWTB across the rails of section ST, and to interrupt the circuit of relay SETR so that its contact 80 thereafter remains released.

The energy supplied from battery BWTB to the rails of section 5T feeds to track relay 5WTR during a released period of the contact of relay SECTM and picks up contact I08 of relay 5W'I'R to establish the circuit of relay SWFSA. Accordingly, the contacts of relay EWFSA pick up so that its contact 32 interrupts the circuit for supply- 7 ing energy to relay SECTM and the contacts of relay EECTM thereafter remain released to maintain the circuit of the relay BWTR and to discontinue the supply of energy from battery 5E'TB to the rails of section 5T with the result that even if the contact of relay EWC'I'M release to connect relay SETR. across the rails of section 5T, the contact 80 of relay '5E'I'R, will remain released and will not establishthe circuit of relay SEFSA.

As pointed out above, on release of relay 4WT'R,

' the circuit of relay 4WFSA is interrupted, and on On release of relay SES at'this time, energy is supplied to relay ECTM over the circuit which includes front contact of relay SEFSA, back contact 98 of relay liES, back contact 93 of relay release of relay 5ETR the circuit of relay SEFSA is interrupted, and these relays release after ex piration of their release periods.

When relay AWFSA releases, its contact 9| interrupts the circuit traced above for supplying energy to relay SWCTM and its contacts release to cut off 'the supply of energy from battery SW'I'B to the rails of section ST and to connect the track relay 5ETR across the rails of section 5T. HowlECTM release and connect relay 4WTR across the rails of section 4T so that steady energy supplied to the section rails at the west end of the section feeds to relay lWTR and picks up its contact 9? to establish the circuit of relay GWFSA and cause its contacts to pick up if they have become released, or to remain picked up if they have not become released.

' On picking up of the contacts of rela AWFSA,

energy is supplied to, relay 5WC'I'M over front contact 9| of relay 4WFSA, back contact N5 of relay 5W8, back contact I86 of relay 5H, and back contact 88 of relay BES, and the contacts of relay 5WCTM pick up to interrupt the circuit of relay 5ETR. and connect the battery EWTB across the section rails. As the'circuit of relay SETR is. in-- terrupted, its contact-8i remains released and does not establish the circuit of'relay SEFSA so the contacts of relay BEFSA remain released.

As relay SWCTM is now steadily energized. the battery SWTB is steadily connected across the rails of section ET and steady energy is supplied over the rails of section ST. so that when section 9'! is vacated, the equipment at theeast end of section '1' operates in the manner just explained to cause steady energy to be supplied to the rails of section 9T,

As previously explained, as long as relay E8 is picked up, relay SFBP is connected over back contact I08 of relay 5WS'and front contact I09 of relay 5E8 to a circuit controlled by contact I0 of relay 4EFB, and to a circuit controlled by contact IIO of relay 4WFSA. As long as section 4T is vacant, the relay IEFB is operated by feedback energy, supplied over the section rails and and its contacts release to establish the circuits to energy to relay 5WCTM and establishes the circuit including back contact 84 of relay SEFSA and back contact 98 of relay 5ES for supplying energy of 180 code frequency to the relay SWCTM;

Accordingly, relay 5WCTM operates to supply energy of 180 code frequency to the rails of section 51 and relay EWTR follows code with the result that relay BTM repeats the track relay and relays 6H and SJ pick up. When relay 6H picks .up, energy is supplied to relay GWS over front contact 21 of relay 6H, back contact 29of relay GEFSA, and front contact 28 of relay 5WFSA light the lamps of signal, SSE and tosupply 7 energy to track transformer 4ETT.

When section 4T is vacated, if th'estretch continues to be conditioned for eastbound traflic, feed-back energy will again be supplied over the section railsto operate rela 4EFB and cause it to establish the circuitbf r lay 5FBP so that its contacts pick up to dis tinue the supply of energy to transformer 4E and to the lamps of signal SSE.

If, at the time section 4T is vacated,steady energy is supplied to the west end of the stretch and is repeated to section 4T, the relay 4WTR will be operated by this energy and will establish the circuit of relay 4WFSA as explained above. When relay 4WFSA picks up, its contact IIO establishes a circuit including front contact I09 of relay5ES for supplying energy to relay 5F'BP and its contacts pick up.

When section 5T is vacated and relay 5ES releases, as explained above, its contact I09 interrupts thecircuit of relay SFBP and this relay releases. On release of relay 5E8, its contact I9 interrupts the circuit of transformer4ETT and short-circuits the transformer primary winding, while contact I2 of relay 5E8 interrupts the circuit of the lamps of signal 58E so that release of relay SFBP is without effect". The relay BFBP operates ina similar manner when section ST is vacated. I If it is now desired to prepare the track stretch for westbound traffic, the steady energy supplied and the contacts'of relayBWS pick up. When relay 6H picks up, the supply of steady energy to relay BWC'I'M is cut off and energy of 180 code frequency is supplied to this relay so that energy of 180 code frequency is supplied to the rails of section 6T. At this time, the code transmitter I80CT is operated by energy supplied over from back contact II5 of relay 5TM, front contact H0 of relay 5H, front contact I I8 ofrelaylIWFSA, back contact II9 of relay 5EFSA, and back contact I20 of relay 4ECTM. Accordingly, contact I22 of relayAWIR picks up so that an impulse of fee 4WBB through the winding of track relay 4W'IR to the rails of section 4T. The resistor I24 connected across the terminals of the winding of at the west end of the stretch is cut off and coded energy is substituted therefor so that cascading of V steady energy through the track stretch is disconrelay IWTR follows code so that energy is. supplied to relay 4WFSA during the picked-up periods of track relay contact 92, while during the released periods of contact 92, energy is supplied over back contactt92, front contact II2 of relay 4WFSA, and back contact 8| of relay SEFSA to relay 5TM. Accordingly, the contacts of relay 5'I'M pick up so that energy is supplied to relay EBSA andits contacts pick up to establish the circuit of the code transmitter 3001' and to also establish the circuit of the primary winding of transformer 5D'I' so that on continued coding operation of relay 5TM the relays 5H and SJ pick up; f v

When relay 5H picks up, energy is supplied over front contact I00 of relay 5H, back contact relay 4WIR, and the resistor I25 connected to the circuit for supplying energ to relay 4WIR, delay release of relay 4WIR. so that the impulse of feedback energy supplied to,the rails of section 4T is of appropriate length. I

In like manner when relay 6H picks up, energy is supplied to relay 5WIR over the circuit which includes back contact I08 of relay 5WTR, front contact H of relay 5WFSA, back contact I6 of relay EEFSA, asymmetric unit 52, back contact 53 of relay BTM, front contact 54 of relay 5H, front contact 51 of relay SWFSA, back contact 56 of relay GEFSA, and back contact 45 of relay 5ECTM.- Accordingly, contact 48 of relay 5WIR picks up so that an impulse of energy is supplied from battery 5WBB through track 'relay 5WTR toe the rails of section 5T, while the resistor 50 connected across the terminals'of relay 5WIR and the resistor 6| associated with the circuit of relay SWIR delay release of the relaysothat the feed-back impulses are of proper duration.

The energy supplied from battery 5WBB to the rails of section 5T feeds to relay 5WFB over the circuit which is traced from the positive terminal,

of battery SWBB over front, contact 48 of relay 5WIR, winding of relay 5WTR from left to right, back contact 31 of relay 5ECTM, track rail I,

back contact 39 of relay 5WCTM, track winding back energy is supplied from battery relay SEC'I'M to the negative terminal of the battery BWBB.

-- The energy supplied from battery ISWBB to" the relay WFB flows through the winding 43 of the relay in the direction to move contact I26 to its right-hand or reverse position in which it establishes the circuit for supplying energy to relay SFBP, while during each picked-up period of the contacts of relay SWCTM the local wind= ing I21 of relay SWFB is energized in series with flows through the windings of track relays SWTR and BETR, but this energy iloyvs through the windings of these relays in the wrong direction to pick up the relay contacts, and operates instead to hold the relay contacts released so there is no danger that the feed-back energy will improperly operate the track relay of either track circuit for section' 5T; 1

Because of the inductance of the track circuit, when the relay 5WIR releases and interrupts the circuit of battery SWBB, energy may continue to flow in the track circuit. However, this energy flows in the same direction as the energy supplied from thebattery and this energy will flow through the winding of track relay EWTR in the wrong direction to pick up the relay contact. The inductive energy from the track circuit will flow through the track winding 65 of relay EEFB in the direction to move contact 49 to its left-hand or normal position, but this movement of contact 49, if it occurs, is without efiect as the ircuit controlled by this contact is open at cont ct 66 of relay 8E8. I

Similarly when relay BWCTM releases and interrupts the circuit of battery SWTB, energy may continue to fiow in the track rails because of the inductance of the track circuit, and when the contacts 39 and 40 of relay EWCTM engage their ba contacts,1 energy from the track circuit will end to flow to track relay BETH and to flow through this winding from left to right, that is, in the direction to pick up the relay contact; However, when the contacts of relay SWCTM are picked up energy is supplied to relay EEIR and its contact 42 is picked up to connect battery SEBB in series with'the winding of relay SETR with the positive terminal of the battery connected to the right-hand terminal of the relay windi g. Accordingly, when the relay SWCTM releases and connects the track rails with 'the winding of relay EETR energy from the battery SEBB flows through the winding of the track relay SETR and prevents picking up of the contact of the track relay by inductiveenergy from the track circuit. At this time, relay SEIR is snubbed only by resistor I30 the section rails in series with the track relay SETR so that the relay ISWFB will respond to feed-back energy supplied over the section rails.

ergy from the track circuit occurring on interruption of the circuit of either'the track or the feed-back battery will not cause operation or the apparatus of the track circuit for either direction It will be seen that-when relay 5H picks/ up,

\ the supply of steady energy to relay BWCTM is cut oil and codedenergy is supplied thereto so that coded energy is supplied to the rails of section ST and operates relay IiWTR so that relay 6I-I picks up. As soon as relay 61:1 picks up, the circuit for supplying energy to relay EWIR is complete and it operates to supply feed-back energy to the rails of section ST and thus to relay EW'FB so that contact I26 oi relay SWFB is moved. to its right-hand or reverse position in which it establishes the circuit for supplying energy to relay SFBP.

When relay 5H picks up, its contact I00 establishes the pick-up circuit of relay 5W8 and its I of relay 5ES and front contact I08 of relay BWS to the circuit controlled by contact I26 of relay 5WFB so that on movement of the contact I26 of relay SWFB to its reverse position by feedback energy, energy is supplied to relay SFBP to pick up its contacts and maintain them tact iSi interrupts one circuit short-circuitin picked up. v

In addition, when relay 5W8 picks up, its conlamps of signal 38W.

on release oi. relay SWCTM the relay BEIR. re-

- picked up for only a very limited interval, after which it releases and connects relay IWFB across When relay 5W8 picks up, its contact 84 interrupts the circuit oi. relay IEC'I'M to insure that its contacts will remain releasedand maintain the circuit of the track relay lWTR, while contact actor relay rws establishes the circuit 101- supplying energy of code frequency to'relay SWCTM on occupancy of section T and release of relay 5H.

The equipment at the east end or section 3T operates in substantially the same manner at this time. When relay 8H picks up, energy is supplied to relay 6W5 and its contacts pick up to place relay GFBP under the control of contact I33 of relay SWFB, and to place transformer 6W'I'1 and the lamps of signal IBW underthe control of relay BFBP.

As pointed out above, when relay IH picks up. coded energy is supplied to relay BWC'IM and it' operates to supply coded energy to the-rails of section 51'' so that relayjW'I'Roperates to pick up relay 6H and thereby cause relay IWIR to operate to supply iced-back energy to the rails SWS picks up, energy will be supplied to transformer 5WT1 and to the lamps of signal SW until relay BFBP pick up. The period required a for picking up of relay BFBP after picking up of relay SWS may be reduced to a minimum by making the relay IWS slow to pick up so that relay 5WS will not pick up until after the equipment at the east end of section ST is conditioned to cause feed-back energy to be supplied to the section rails. This insures that when relay GWS picks up to place relay SFBP under the control of relay SWFB, the relay SWFB will be. operated by feed-back energy so its contact I26 will establish the circuit of relay BFBP.

The equipment for the other track sections operates in substantially the same manner as that for section 5'! so that the supply of coded energy is cascaded through the remaining track sections to the east end of the track stretch to cause the headblock signal at that point to display a permissive indication and thus authorize a westbound train to enter the track stretch.

On movement of a westbound train through the track stretch, the equipment operates in subtil short-circuits the primary winding of track transformer SWT'I', while relay 5E8 is picked up so that'its contact I09A connects relay SFBP to the circuit controlled by contact "III of relay 4WFB and by contact N of relay QWFSA, and contact 19 of relay E8 connects primary winding of track transformer 4ETT.to contact ll of relay SFBP. .As the stretch is assumed to be vacant, feed-back energy supplied over the rails of section 4T moves contact of relay 4WFB to its normal position in which it establishes the circuit of relay SFBP so that the contacts of relay SFBP are pickedup.

Accordingly, contact '11 of relay SFBP shortcircuits the primary winding of track transformer GETT, while contact ll interrupts the circuit for supplying energy to the lamps of the wayside signals, and contact I interrupts the circuit for supplying direct current to thetuned alternator.

When an eastbound train enters section 4T, the supply of feed-back energy over the rails of section T is cut oil and contact 10 of relay 4EFB no longer establishes the circuit of relay 5FBP and its contacts release and contact I35 establishes the circuit for supplying energy to the tuned alternator so that it operates to supply alternating current to the associated transformer, while contact ll of relay SFBP connects the primary winding of track transformer 4EI'I to the transformer associated with the alternator with the result that coded alternating cu rent is supplied to the rails of section 4T. In addition, on

stantially the same manner as it does on movement of an eastbound train through the track stretch, and a detailed description of the operation of the apparatusis unnecessary.

Similarly, when the stretch is being conditioned tor eastbound traffic, the equipment operates in substantially the same manner as it does when the stretch is being conditioned for westbound trafilc, and a detailed description of the operation of the equipment at such times is unnecessary. I

Modification shown in Fig. 2

As explained above, the system shown in Fig. 1 operates so that when traillc is being established for either direction, energy is not supplied tothe approach control relays FBP until one or,

the other of the associated directional stick relays picks up, while when a directional stick relay is picked up and the relay FBP is released, energy is supplied to a track transformer and to the lamps of one of the wayside signals. Accordingly, the system of Fig. 1 operates at such times" to cause momentary lighting of the lamps of a wayside signal and momentary supply of cab signal control energy to the track stretch.

It maybe desired to eliminate this flashin of the wayside signals and momentary supply of cab signal energy to the track rails, particularly where tuned alternators are employed to supply the alternating current cab signal energy, and

front contact 109A of relay SES for supplying release of relay 5FBP its contact 1| establishes the circuit for supplying energy to the lamps of signal ESE.

AWTR. picks up and its contact 92 establishes the circuit of relay 4WFSA so that its contacts pick up and contact H0 establishes a circuit including energyto relay SFBP. Accordingly, the contacts of relay SFBP pick up to cut off the supply of energy to the alternator and to the lamps of the wayside signals, while the primary winding of' track transformer lETT is short-circuited. Y

When section ST is vacated, relay EEFSA is picked up to interrupt the stick circuit for relay 5E8, as explained in connection with Fig. 1, and relay SES releases so that its back contact-I093 establishes a circuit including back contact IIJBA of relay 5WS to energize relay EFBP and its contacts remain picked up to interrupt the circuit of the alternator and of the lamps of the wayside signals. In-addition, on release of relay 5E5 its contact I09A interrupts the circuits controlled by relays 4WFSA and QEFB for supplying energy to relay SFBP, while contact [9 of relay 5E8 interrupts the circuit for supplying energy to transformer 4E'I'I and short-circuits the primary winding of this transformer.

If the stretch is now to be prepared for west- I bound trafiic, the supply of steady energy to the west end of the stretch is cut oil, and coded energy is substituted therefor, while as explained in connection with Fig. 1 this coded energy is cascaded through the various track sections. I

On the supply of coded energy to track relay 4WTR, energy is supplied over its back contact 92, iront contact N2 of relay AWFSA, and back over the section rails.

contact 8| of relay 5EFSA to'the relay STM so that it operates to pick up relay 5H and complete the circuit for supplying coded energy to the rails of section 5T, and thus cause the equipment at the right-hand end of section 5T to operate to supply feed-back energy to the section rails to thereby cause contact I26 of relay 5WFB to be moved to its right-hand or reverse position.

In addition, as explainedin connection with Fig. 1, when relay 5H picks up, it establishes a pick-up circuit for relay 5WS but relay 5WS is of a'type the contacts of which are slow to pick up so' the relay does not pick up until after coded energy has been supplied to the rails of section 5T long enough to initiate operation of relay establishes the circuit of relay 5FBP and keeps its contacts picked up.

As previously pointed out, energy is supplied to relay 5FBP over back contacts of relays 5WS and 5ES until relay 5WS picks up, while relay 5WS is slow to pick up so that track circuit apparatus for section 51 is conditioned to cause feed-back energy to be supplied over the section rails before relay 5WS picks up. At this time,

the track circuit apparatus for section 5T is operated by energy of 180 code frequency so there is little delay in the supply of feed-back energy Accordingly, when relay 5WS picks up to interrupt the circuit including back contact I09B of relay 5ES for supplying energy to relay 5FBP and to connect relay SFBP to the circuit controlled by contactfl26 of relay 5WFB, the relay 5WFB is operated by feed-back energy and contact I29 establishes the circuit of relay 5FBP. Furthermore, relay SFBP is of a type the contacts of which are slow to release so that if at the time relay 5W8 picks up, contact I26 of relay 5WFB is in its left-hand or normal position, the contacts of relay 5FBP will remain picked up until contact I of relay 5WFB is moved to its reverse position. During preparation of th track stretch for westbound trafllc, therefore, relay 5FBP remains picked up and prevents suoply of'ener y to the tuned alternator and to the-lamps of the wayside signals.

In like manner, the relay 5FBP remains picked up when t e stretch is being prepared for eastbound trafflc. The operat on of the equipment at such times is substantially the same as when i the stretch is being prepared for westbound trafllc and a detailed explanation'of the operation of the equipment is unnecessary.

Modification show'in in Fig. 3

- tion of traffic, while the equipment at adjoining ends of the two sections is arranged so that coded or steadyenergy supplied to one of these sections will be repeated to the other one of these sections. In addition, each of these trac sec-- tions is provided with approach control facilities operated by feed-back energy togovern the 'supply of alternating current cab signal control energy to the section rails.

Only the equipment atthe adjoining ends of the two sections is shown in Fig. 3, and the equipment at the other ends of these sections may be the same in construction and operation as that shown in Fig. 1- or 2.

The apparatus of Fig. 3 is shown in the condition which it assumes when the track stretch is vacant and is conditioned for eastbound trafllc. At this time, coded energy is supplied to the rails of section EIT at the right-hand end thereof and this energy feeds over back contacts I40.

andI4I of relay E'IWCTM, and back contact I42 of relay EIEIR and picks up the contact I48 of track relay ElETR, and moves the contact of relay EIWFB to its left-hand or normal position., I I

When relay E'IETR picks up, energy is supplied to relay E'I'EFSA over back contact I44 of relay W'IWFSA, back contact I45 of relay W'IWTR, and front contact I46 of relay EIETR so the contacts of relay E'IEFSA are picked up. Accordingly, during the released periods of relay E'IETR, energy is supplied over back contact I44 of relay W'IWFSA, back contact I45 of relay W'IWTR,

back contact I45 of relay E'IETR, and front contact I48 of relay E'IEFSA to relay lBSA so its contacts are picked up.

As relay lBSA is picked up, its contact I49 interrupts the circuit which it controls for supplying energy" to relay 'IFBP, while contact I50 establishes a circuit for energizing relay WlECTM in multiple with relay 'IBSA during the released periods of relay EIETR. The circuit for supplying energy to relay WIECTM includes back contact I44 of relay W'IWFSA, back contact I45 of relay W'IWTR, back contact I48 of relay EIETR,

front contact I48 of relay EIEFSA, front contact I50 of relay 'IBSA, back contact I5I of relay WIWFSA, and front contact I53 wf, relay EIEFSA. Accordingly, during each released period of the contact of relay E'IETR energy is supplied to relay WIECTM and its contacts pick up to supply energy from battery WIETB to the rails of section WIT, while during the picked-up periods of the contact of relay EIETR the circuit of relay W'IEC'IM is interrupted and its contacts I release. The relay WIECTM, therefore, operates to supply to section WlT energy of the same code frequency as that supplied to relay EIETR, but

with the on periods in the coded energy supplied to section W'IT occurring during the o periods in the code supplied to section E'IT.

On release of relay E'IERT to establish the circuit of relay WlECTM the contacts of relay WIECTM do not pick up instantaneously and, in the period during which they remainreleased, energy is, supplied to relay EIEIR over the circuit which includes back contact I44 of relay WIWFSA, 6 ck contact I of relay w1w'ra,

v back contact I45 of relay EIETR, front contact I48 of relay E-IEFSA, front contact I of relay 'IBSA, back contact I5I of relay WlWFSA, front contact I of relay E'IEFSA, back contact I54 of relay WIECI'M, back contact I55 of relay W'IWFSA, and "back contact I56 of relay EIWCTM. The supply of energy torelay E'IEIR' is interrupted as soon as contact I54 of relay W'IECTM picks up, but the energy supplied to relay EIEIR prior tothis time picks up the relay contact, while the resistor I51 connected across the terminals of relay EIEIR, and the resistor assaasa Ill connected to the energizing circuit for relay -E'IEIR, delay release 01' the relay long enough to cause the impulse of teed-back energy supplied to the 'rails of section EIT to be of adequate duration.

When the contact I42 of relay E'IEIR picks up, feed-back energy is supplied from battery EIEBB through the winding of track relay EIETR to the rails of section -E'IT. This energy flow through the winding of relay E'IETR. in the wrdiig direction to pick up the contact of this relay, while the energy supplied from the battery E'IEBB to the rails of section E'IT operates the feed-back detector relay at the right-hand end of section E'IT.

When relay WIECTM picks up, its contact I60 establishes the circuit to energize the relay contact I69 of relay *IFBP releases and establishes the circuit including front contact I of relay EIEFSA for supplying energy to trans.- former W'IETT so that on continued coding op-' eration of relay W'IECTM, coded alternating cur-' rent cab signal control energy is supplied to the rails of section WIT to operate the cab signal equipment on the locomotive in that section.

W'IWIR and the lower winding 01 relayW'IEFB.

in series so the contact I62 of the relayW'IEFB is moved to its right-hand or reverse position in which it interrupts the circuit of relay 'IFBP. The energy supplied to relay WIWIR picks up its contact I so that battery WTWBB is connected' in series with .the winding of the track relay WlWTR. but as long as relay WIEC'I'M is picked up, no energy flows from the battery WIWBB.

On release of the relay WIEC'I'M, contact I60 interrupts the circuit ot'relays WIWIR and WIEFB, and the relay WIWIR releases after a ,short time interval determined by the resistor I connected across the terminals of the relay winding. In the period after release of relay WIECTM and prior to release of relay WIWIR,

1 energy is supplied from battery W'IWBB through relay WIWTR to the section rails and prevents operation of relay W'IWTR by inductive energy from the track circuit occurring on release of the relay WIECTM and interruption of the circuit of the battery W'IE'I'B. The resistor I65 delays release oi. relay WIWIR for only a very shortperiod, and on release of contact I64 of relay WIWIR the elays WIEFB and W'IW'I'R are connected in series across the rails of section W'IT so that the impulse of feed-back eny supplied over the rails of section WIT at this time moves the contact I62 of relay WIEFB to its left-hand or normal position, but does not pick up the contact of relay W'IWTR.

0n movement'of contact I62 of relay W'IEFB to its left-hand position, energy is supplied to relay 'IFBP, over the circuit including contact III of relay W'IEFB, back contact I61 of relay WIWFSA, and front contact I68 of relay E'IEFSA, so the contact I69 of relay IFBP is picked up to prevent supply of energy to transformer W'IETI' and to short-circuit the primary winding of this transformer.

.When the train advances into section E'IT, the

; track relay E'IETR is shunted and ceases to establish the circuit of relay E-IEFSA and it re- .leasesto interrupt thecircuit of relay IBSA so' that its contacts release. On releaseof relay 'IBSA, its contact 9 establishes a circuit to supply energy to relay 'IF'BP and its contact I88 is picked up to prevent supply of alternating current to the circuits controlled by this contact. In addition, on release of relay 'IBSA, its contact I interrupts the circuits for supplying coded energy to the coding relays and establishes a circuit over which steady energy may be supplied to one or the other of these relays. On release of relay EIEFSA, its contact I53 interrupts the circuit traced above for supplying coded energy to coding relay W'IECTM, while contact I68 of relay E'IEFSA interrupts the circuit controlled by contact I62 of relay W'IEFB for supplying energy to relay 'IFBP, and contact I10 of relay EIEFSA interrupts the circuit for supplying energy to transformer WlETT- and short-circuits the transformer primary winding.

When section E'IT is occupied, the supply of feed-back energy to the section rails is cut on and the 'equipmeht at the right-hand end of this section operates to cause coded alternating current cab signal-control energy to be supplied to the section rails.

As explained in connection with Fig. 1, on movement of a train through the track stretch steady energy may or may not be supplied to the stretch in the rear of the train depending on During the picked-up periods of the relay I WlECTM, the contact I62 of relay WIEFB is moved to its reverse position in which it interrupts the circuit of relay 'IFBP, but the relay IFBP is slow enough in releasing to remain picked up during -these periods. Accordingly, when the'stretch is conditioned for eastbound it tramc, the relay IFBP is connected to the circuit controlled by contact I62 of relay WIEFB, while as long as section W'IT is vacant, relay WIEFB is operated by feed-back energy supplied over the section rails and maintains relay 'IFBP energized.

whether or not another train is to be permitted to pass through the track stretch.

If steady energy is no'tsupplied to the west end oi the track stretch, the equipment will remain as described until section ET]? is vacated, at which time coded energy supplied at the right-hand end of the section operates relay E'IETR so that relays ElEFSA and 'IBSA are picked up to thereby cause relay. WTECI'M to" operate as a repeater of relay E'IE'IR and to place relay -'IF'BP under the control of relay W'IEFB.

If steady energy is supplied to the west end of the stretch, it will be cascaded through the various sections as they are vacated, as explained in connection with Fig. 1. As will be understood from Fig. l, the equipment at a signal location operates in such manner that steady energy is not supplied to a section until the section. is vacated and an impulse of coded energy is supplied over the section rails.

When an easbound train enters section WIT,

the supply of feed-back energy over the section rails is cut oil and contact I62 of relay WlEFB remains in its reverse position in which it interrupts the',circuit of relay IFBP. Accordingly. the

to relays E1EF'SA, 138A and W1E'CTM. Accordingly, the contacts of relay WIECTM remain released and maintain the circuit of relay 'WIW'I'R so that the contact of relay W1WTB, re-

mains picked up. After a short time interval,

, the contacts of relay E1EFSA release so that energy is supplied over back contact I48 of relay v E1WCTM. This insures that rela E1EIR will EIEFSA, back contact I48 of relay E1ETR, and front contact I45 of"'relay W1WTR to relay W1WFSA and its'contacts' pick up.. Relay lBSA'also releases at this time so energy is supplied over'its back contact I49 to relay 1FBP,

E1WFB soon enough to make while energy is supplied over back contact 155 of relay 1BSA, back contact I53 of relay ElEFSA,

and front contact I5I of relay W1WFSA to relay I E1WC'IM and its contacts pick up to cause steady energy to be supplied to-the railsof section E1T,

and thus cause steady energy to be repeated throughout the track stretch.

'If the steady energy supplied to the west endof the track stretch is cut oil and coded energy substituted therefor, this coded energy will be cascaded through thetrack stretch so that coded energy is supplied to the west end of section W11.

- On the supply of coded energy to section W1T the relay W1WTR follows code, and energy is supplied to relay 1BSA during the released periods of the contact of relay W'IW'IR, and the contacts of relay 1BSA ;pick up with the result that, during" the released periods of relay W1WTR, energy is suppliedto coding relay E1WCTM over the circuit which includes back contact I48 of relay E1EFSA, back contact I46 of relayE1E'I'R; back contact, I45 of relayWlWTR, front contact I44 of relay. W1WFSA, front contact I50 of relay J1B SA, back contact I58 of relay ElEFSA, and front contact I5I of I relay ,W'IWFSA. Accordingly, relay' E1WCTM operates as a back contact repeater of track relay W1WTR and causes coded energy to besupplied to the rails of section E1T.

Inaddition, at this time, energy is supplied to relay W1WIR over the "circuit traced above for relay liflWQTM, plus the branch which includes back contact I12 of relay E1WCTM, back contact I18 of relay E1EFSA, and back contact I50 of re-' to thel rails of section W1T lay W1ECTM, so'the relay operates to,

cause impulses of feed-back energy to be supplied I during the ofi" periods in the code supplied to'that section. The circuit for energizing the relay W1WI;R has the resistor I14 associated therewith, and this resistor together with the resistor I55 connected' acro'ss the terminals of relay W1WIR delays releaseof the relay enouglrt'o cause the feedeback irrlpulses suppliedto section-W1T to be of proper duration. The. resistor I14 is connected with the circuit at such a point in the circuit that it isrisolated froni relay E1WCI'M as soon as the contacts of J relayE1WCTM ick up.. This prevents the resistor I14 from affecting the release of relay EiWCTM with resultant supplied to the rails of section 1311'.

During the picked-up periods of relayE'IWCTM, its contact I55 establishes the circuit to energize relay E1EIR in series with the local winding of relay E'IWFB so-that contact I4 2 of relay E1EIR is picked up to connect battery 'EFEZBBLin series with the relay El'ETR and thus prevent operation of relay E1E'I'R by inductive energy from the trackcircuit on release of. relay E1WCTM. On release of relay E1WCTM contact I55 interrupts the circuit of relay ElEIR and connects the relay windins to the wire leading to the back conthat shown in Fi 3 and assumes when the stretch tioned'for eastbound traflic. EIIETR is operated by coded distortion of the code mama is interrupted assaosa li long release of relay E1EIR. Accordingly, at this time, the release period of relay E1EIR is determined solely by resistor I51 which may be of such value as to delay release of relay ElEIR for only a short period subsequent to release of relay 20 terfere with the proper operation of theequipment when the stretch ,is conditioned for eastbound tra-fflc.

At this time, relay 1BSA is. picked up so its contact I49 interrupts the circuit which it controls for supplying energy to relay 1FBP, but at this time relay 1FBP! is connected over front contact- I51 of relay W1WFSA and back contact I58 of relay E1EFSA to the circuit controlled by contact I15 of;relay ETWFB so that on operation of re-- lay E1WFB by feed-back energy the relay 1FBP is maintained picked up to prevent supply of alternating current to the track transformer E1WTB. g

' On movement of. a westbound train through the track stretch,'the equipment operates in substantially the same manner as it operates on movement of an eastbound train through the track stretch and a detailed description of the op- 46 eration of the euuipment is unnecessary.

Modification shown in Fig. 4 In Fig. 4 there is shown cut section apparatus The equipment shown in Fig. 4' is similar to differs therefrom in that the coding relays WCTM and ECTM are energized over front contacts of the track relays, while the impulse relays are energized over front contacts of the coding relays. I The operation of the equipment shown in Fig, 4 is similar to that shown in Fig. 3. The equip-" ment of Fig. 4 is shown in is .vacant and is condivAt. this time, relay I energy supplied over the rails 0t section E8T and during the picked-up periods of the relay contact I18 energy is supplied to relay E8EFSA and to relay WBEC'I'M, while 6Q during the released periods. of relay EIiETR the relay W8ECTM releases, andcnergy is supplied to relay 8135A and its contacts are picked up so that on rleaseof relay E8ETR energy is supplied to relay EBEIR over the circuit including from contact I8l ofrelay SBSA- back contact I82 of relay WBWFSA, front contact I83 of relay EBEFSA, front contact tact I85 of relay WBWFSA, and back contact I85 of relay EBWCTM. The supply of energy. to relay as soon as relay W8EGTM releases, (but sufilcient energy is supplied to relay ESEIR in the period between release of relay I EBETR and release of relay WBECTM to pick up the relay E8EIR, while'thexesistors associated with relay 128E113. delay 1' lease of itscontacts the condition which it which may be employed at cut-sections where front contact coding is desired.

I84 of relay WBECTM, back conrectional-stick relays wan-anding the picked-up period of relay EBEIR, are of adequate duration.

During the picked-up periods of relay WOECTM, its contact I 8'! establishes the circuit to energize relay WSWIR and the local winding of relay WBEFB so the contact [88 of relay WIEFB is moved to its reverse position, while contact I of relay WBWIItpicks up to connect battery wawBB in series with the track relay WIW'I'R to prevent operation of the relay WSW-TR. by inductive energy from the track circuit.

\ During the released periods of the contacts of relay WlECTM, feed-back energy supplied over the railsof section WB'I' energizes relay WBEFB and moves its contact I88 to its normal position so that energy .is supplied-over this contact back contact Ill .of relay W8WFSA, and front contact I92 of relay ESEFSA to relay OFBP, and its contact is j picked up to prevent supply of energy to The equipment of Fig. 5 is shown in the conditlon which it assumes when the stretch is vacant and is conditioned for eastbound trailic. At this time, coded energy is supplied to the rails of section ET at the right-hand or east end thereof and feeds to track relay ETR. over the circuit which is traced from track rail I, over back contact 203 .of coding relay E TM, winding of relay ETR from right to left, ack contact 204 of impulse relay'EIR, track winding 205 of relay EFB, and back contact 201 of relay ETCTM to rail 2. The energy supplied to the rails of section ET is ofthe proper polarity to pick up the contacts of relay ETR, while this energy moves the contact 209 of relay EFB to its reverse position,

When relay E'I'R picks up, its contacts 2| 2/ and 2 connect line wires 200 and toth terminals-B and C of a source of current so that track transformer'wtE'l'r and -to short-circuit the transformer primary winding. On movement of a train through the stretch, this apparatus operates in a manner similar to the back contactcoding equipment shown in Fig.

3, and a detailed tracin of the circuits is unnecessary. Similarly, the equipment operates in a manner similar to that of Fig. 3 on a change in the established direction of trafllc.

Modification shown m Fig.- 5

In track stretches equipped with signaling apparatus of this type, the-approach sections to-a 2 ghway crossing may be equipped with'tra'ck the positive terminal B is connected to wire 200.

e energy supplied to the line wires flows from terminal B over front contact 2H) of relay ETR to'wire'20ll, over back contact N3 of relay W TR, winding of coding relay WTCTM from left to right, back contact 2 ll of relay WIRA, line winding 2l5 0f relay WFBA from left to right, back contact 2l8 of relay WTR, wire 2!", front contact2ll of relay WATR, front contact H8 01 relay' OTR, front contact 2l9. of relay EATR, and

to the rails of the approach sections, and one means for controlling the supply of coded cab signal energy to the approach sections is shown in my application for Letters Patent of the United States, Serial No. 516,363, filed December 31, 1943, now Patent No. 2,357,235, issued August 29,- 1944.

As shown in Fig. 5 the track stretch includes a' highway intersection which is protected by crossing signals XS, while the track section which includes the intersection is divided into an intermediate section OT which includes the crossing, a westbound approach section EAT, and an eastbound approach section WAT. The remainder oi the track section is completed by sections The track sections-WAT, or and EAT are provided with track circuits employing steady energy, while the sections WT and ET are provided a with track circuits employing coded energy. Only employed in the track stretch is.-transmitted around the approach sections by mcans'of a line circuit consisting of line wires 200 and 20! which are governed by the track relays of the sections WAT, o'rana EAT. v r 1 The crossing signals XS are governed by a relaylli which is controlled by the track relays or the seEt'ionsWAT, Oriana EAT, and by dimaybe arranged as shown front contact 2 of relay E'lltwtd terminal C.

The energy supplied over the line wires to coding relay WTCTM picks upits contacts so that energy is supplied from battery'WTETB over front contacts 22land 222 of relay WTCTM to the rails of section WT to operate the equipment at the west end of the section. a When relay WTCTM is picked up, its contact 226, establishes a circuit to energize relay WIR and the local winding of relay WFB in series so that contact 224.01 relay WFB is moved to its left-hand or normal position in which it interrupts the circuit of relay WFBP, while contact 228 of relay Will. is picked up tcsconnhhhattery WBB in series with the winding of relay WTR to thereby prevent operation of relay WTR. by inductive energy ,from the track circuit on reas explained in connectime thecontacts of relay WTCTM release to interrupt 1 the supp y of energy frombattery WTETB to the rails of section WT, and to interrupt the circuit of relay wntso that its contact. 228 releases to connect reIays'WTR and WFB across the section rails. Accordingly, feedback energy supplied over the rails of section WT moves the contact 224' of relay WFB to itsrighthand or reverse position in which it establishes the circuit of relay WFBP to thereby cause its contact 225 tobe picked up and short-circuit the j primary cs 1 ding of transformer W'I'I.

WTCTM, energy is supplied. through the-associated decoding transformer torelay WT? and its contact 229-.ispicked up to permit energy to be supplied to transformer. W'II on release of relay WFBP. In addition, impulses of energy are" supplied from a secondary winding-oithe decoding transformer to impulse relay WIRA which is of a type which, responds to energy of one nolarity only. The apparatus is arranged so that the energy impulses supplied to relay WIRA on As a r I t of coding operation of relay

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