US2138880A - Train describer system - Google Patents

Description

Dec. 6, 1938. w. T. POWELL 30 TRAIN DESCRIBER SYSTEM Filed Oct. 8, 1936 4Sheets-Sheet 1 BY w TTORNY Dec. 6, 1938. w. T. POWELL TRAIN DESCRIBER SYSTEM 4 Sheeis-Sheet 2 Fi led 060. 8} 1936 INVENTO v :7?

Dec. 6, 1938. w. T. POWELL TRAIN DESGRIBER SYSTEM Filed Oct. 8, '1936 4 Sheets-Sheet 3 ZW YWM,

v.3 m QmN mmu mmm m FL QN F JbN 3 m I ma kit J l Tm S It h MON Dec. 6, 1938. w. T. POWELL TRAIN DESCRIBER SYSTEM 4 Sheets-Sheet 4 Filed 001;. 8, 1936 E, v b 3 mum at mum INVEI VTOR BY um @WM, 12% ATTORNEY mmm mmm T TTU m Ln 5m 11" 7 5 50mm m Patented Dec. 6, '1938 UNITED STATES 2,138,880 7 V, TRAIN pnsonmna SYSTEM Winfred T. Powell, Rochester, N. Y., assignor to General Railway Signal Company, Rochester,

Application October 8,

22 Claims.

This invention relates to railway train route indicating apparatus and it pertains more particularly to the provision of novel and improved means for transmitting from one location along a track layout to a second station or central oflice, descriptions or particulars relating to trains passing the first or transmitting stations, the apparatus being such that the descriptions or indications may be received and displayed at the receiving station for the purpose of indicating the classes of approaching trains.

This invention is in the nature of an improvement over the prior application of Phinney Ser. No. 98,545 filed August 29, 1936, and no claim is made herein to any invention disclosed in said Phinney application.

The present invention is particularly related to a system in which means are operable from the cab or'a locomotive to selectively indicate the classes of various approaching trains. More specifically, it is proposed to provide an arrangement of trackway apparatus and circuits responsive to whistle blasts from a locomotive to accordingly select and energize train identification lamps at a remote location in accordance with codes transmitted by these whistle blasts. It is furthermore proposed to provide an arrangement of trackway apparatus and circuits which will be distinctively conditioned by the presence or absence of whistle blasts at a plurality of steps of a stepping mechanism, at the transmitting station, operating in cycles of operation.

It is further proposed, in accordance with the present invention, to provide a microphone sensitized when the train is in the particular track section with which the train describer apparatus is associated, this microphone being associated with a line circuit leading to the distant location, at which indications are to be displayed and responsive to the codes provided by the whistle blasts for translating and transmitting these codes over the line circuit.

Other, objects, purposes, and characteristic features of the present invention willbe in part obvious from the accompanying drawings and in part pointed out as the following description progresses.

In describing the invention in detail reference will be made to the accompanying drawings in which:--

Fig. 1 indicates the apparatus and circuit arrangement associated with a section of trackat a location from which train identification codes are transmitted.

Fig. 2 illustrates the apparatus and circuit ar- 1986, Serial No'. 104,683

rangement of'the central ofiice apparatus which is responsive 'to the occupancy of the track section and the actuation of the microphone illustrated in Fig. 1.

Fig. 3 illustrates a modification in which the "5 track section shown in Fig. 1 is replaced by four separate insulated track sections and in which the stepping relay bank shown in Fig. 1 is eliminated.

Fig. 4 illustrates the apparatus and circuit arrangement in the central office which operates in connection with the'apparatus at the distant location illustratedin Fig. 3.

The symbols'(+) and are employed to indicate the positive and negative terminals respectively of suitable sources of current and the circuits with which these symbols are used always have current. flowing in the same direction, that is from to It'is believed that the features of the present invention may be best understood by considering the detailed operation of the system, assuming a particular code combination being transmitted fromthestation illustrated in Fig. 1 to the centralofiice illustrated in Fig. 2, after which the operation of a similar code being transmitted from the station illustrated in Fig. 3 to the central ofiice illustrated in Fig. 4 will be pointed out.

Operation Normal conditiona-Referring to'Fig. 1, it is assumed that the section of track comprising rails 6 and insulated joints 5 is unoccupied and consequently track relay T is picked up. An obvious circuit is completed .at front contact 20 of relay '1 for energizing relay TP. All other relays, lamps and microphone MC- in Fig. 1 are normally de-energized. All of the relays and 'lamps in the central oflice (Fig. 2) are normally de-energized, except relay M which is normally picked-up, it being assumed that amplifier AMP is continuously energized.

Stepping operation-It will now be assumed thata train enters the illustrated track section 5 (Fig. 1) Whichis effective to drop relay T. after which relay 'I'P is dropped. It will furthermore be assumed that the description of this particular train requires a code transmitted at steps 1, 2, 3, and 4 of the stepping mechanism for lighting train identification lamp H10 in Fig. 2.

Itwill be understood that the engineer of the train may be supplied with a card indicating the code number of his train, or he may rely on his memory for this code combination. It will furthermore be understood that each different train identification to be transmitted requires a whistle blast at different combinations of steps of the stepping mechanism, these steps being indicated to the engineer by the lighting of the four lamps illustrated in the circle in the righthand portion of Fig. 1. In the case assumed for example, the engineer will blow the whistle at each lighting of lamps I, 2, 3, and 4 as these lamps are lighted in rotation.

It will be readily understood that a combination requiring the transmission of a code only at step 1 for example, would require the engineer to blow the whistle only when lamp I is lighted. It will be observed that sixteen different code combinations are possible by blowing the whistle at the four steps of the cycle as these steps are counted off and indicated by the lighting of the four lamps in the circle. Fifteen of these codes may be used, the sixteenth being left blank for the reason that certain trains may pass this location without desiring to transmit their identity and the whistle not blown.

The dropping of relay '1? closes a circuit at its back contact 2I for energizing microphone M0 by way of choke coil CK from battery MB. The differential type microphone is illustrated, with the two buttons connected to separate primary windings of transformers TF The ad vantages of the differential type microphone are well known, such as the improved amplification due to the double action of the microphone buttons and such as the absence of any magnetizing effect on the core of the transformer from the direct current from battery MB.

The dropping of relay TP also closes a circuit for energizing the line and picking up relays F and 2F, at the station and in the oflice respectively. This circuit may be traced from the terminal of battery LB (see Fig. '2), winding of relay 2F, back contact IOI of relay E, lower inductance of the filter, line conductor 2L, winding of relay F back contact 22 of relay TP, secondary winding of transformer TF line conductor IL and upper inductance of the filter to the terminal of battery LB. Since relay IF in the office is short-circuited at back contact IOI the line circuit will be energized with a comparatively high degree of energization.

The picking up of relay F closes a circuit for picking up relay VP which extends from back contact 23 of relayTP, front contact 24 of relay F back contact 25 ofrelay IV and winding of relay VP to Relay VP closes a first stick" circuit for itself at its front contact 26 whi'ch'is independent of front contact 24 of relay F I a In the central office, the picking up of relay 2F closes an obvious circuit at its front contact I02 for picking up relay SA, and relay SA closes a circuitfor picking up relay FB extending from front contact I03 of relay SA, back contact I04 of relay FC, and winding of relay FB to Relay VP is picked up over a circuit extending from front contact I05 of relay SA, front contact I06 of relay FB, back contact I01 of relayIV and winding of relay VP to Relay VP closes a first stick circuit for itself at its front contact I08 which is independent of front contact I06 of relay FIB Relay E is now picked up over a circuit extending from front contact I03 of relay SA, back contact I09 of relay 2V, back contact IIO of relay IV, front contact III of relay VP, and winding of relay E to The picking up of relay E removes the short circuit from relay IF at open back contact IOI, which inserts the high resistance winding of relay IF in the line circuit for reducing the energization of the line from a high value to a low value, which is effective to drop relay 2F in the office and relay F at the station. Relay IF being of very high resistance and therefore sensitive, picks up and closes a substitute circuit for relay SA at front contact II2 to maintain relay SA energized after front contact I02 of relay 2F is opened. It will thus be seen that relay SA needs to be only slightly slow releasing so that it will be held up during the time it takes relay IF to pick up after the operation of relay E. It will be pointed out at this time that relays FA, FB, FC and E are impulsing relays for applying stepping impulses to the line circuit at a definite rate, which rate may be determined by the slow acting characteristics of these relays.

The dropping of relay 2F closes a circuit for picking up relay FA which extends from back contact I02 of relay 2F, front contact H3 of relay SA, and winding of relay FA to Relay EC is now picked up over a circuit extending from front contact I03 of relay SA, front contact II4 of relay FA, and winding of relay FC to The picking up of relay FC deenergizes relay FB at open back contact I04 and relay FB drops after a predetermined interval of time.

A second stick circuit is now closed for relay VP extending from front contact I05 of relay SA, back contact I06 of relay FB, front contact H5 and winding of relay VP to Relay IV is now picked up over a circuit extending from front contact II6 of relay'SA, back contact II'I of relay FB, front contact II8 of relay VP, back contact I I9 of relay 2V and winding of relay IV to Relay IV closes a stick circuit for itself which extends from front contact H6 of relay SA, front contact I20 and winding of relay IV to Referring to the field station, the dropping of relay F closes a. second stick circuit for relay V'P extending from back contact 23 of relay IP, back contact 24 of relay F front contact 21 and winding of relay VP to Relay IV is picked up over a circuit extending from back contact 28 of relay TP, back contact 29 of relay F front contact 30 of relay VP back contact 3! of relay 2V and winding of relay IV to Relay 'IV closes a stick circuit for itself extending from back contact 28 of relay TP, front contact 32 and winding of relay IV to Referring back to the office, the picking up of relay IV de-energizes relay E because of open back contact H0 and the dropping of relay E short-circuits the winding of relay IF at back contact IM to provide a high degree of energization of the line circuit, which is effective to pick up relay 2F in the oflice, drop relay IF in the ofiice and pick up relay F at thestation.

The picking up of relay F at the station drops relay VP because its first stick circuit is open at back contact 25 of relay IV and its second stick circuit is open at back contact 24 of relay F Referring to the office, the picking up of relay 2F drops relay FA because of open back contact I02 and the dropping of relay FA drops relay FC because of open front contact H4. Relay FB is again picked up because of closed back contact I 04 of relay FC. Relay VP isdropped because its first stick circuit is open at back contact I01 of relay IV and its second stick circuit is open at back contact I06 of relay FB.

RelayE is now picked up over the above described circuit, which now extends through back contact III of relay VP and front contact I III of relay IV.

.an obvious stick circuit for itself at its front contact 34.

Referring to the oflice, relay PA is picked up because of closed back contact I02 of relay 2F and relay FC is picked up because of closed front contact II4 of relay FA. Relay F3 is. dropped because of open back contact I04 of relay FC and relay 2V is picked up over a circuit extending from front contact II6 of relay SA, back contact II'I of relay FB,,back contact II8 of relay VP, front contact I 2I of relay IV, and winding of 2V to Relay 2V closes an obvious stick circuit for itself at its front contact I22. The picking up of relay 2V drops relay E because of open back contact I09 and relay E again short circuits the winding of relay IF to apply a high degree of energization to the line.

In response to this high degree of energization, relays F and 2F are picked up and relay IF is dropped as before. At the station, relay VP is again picked up because of closed front contact 24 of relay F and closed front contact 35 of relay 2V The first and second stick circuits of relay VP are effective as previously described.

In the office, relay FA is dropped because of open back contact I02 of relay 2F and relay F is dropped because of open front contact II 4 of relay FA. Relay F3 is picked up because of closed back contact I04 of relay FC, and relay VP is picked up because of closed front contact I06 of relay FE and closed front -contact I23 of relay 2V. The first and second stick circuits for relay VP are effective as previously described. The picking up of relay VP picks up relay E, because of closed front contacts III and I09 of relay VP and 2V respectively, and the picking up of relay E again removes the short circuit from the winding of relay IF for applying a low degree of energization to the line circuit, which effects the dropping of relays 2F and F and the picking up of relay IF as before,

Relay FA is now picked up because of closed back contact I02 of 'relay 2F, relay F0 is picked up because of closed front contact H4 of relay FA, and relay FB is dropped because of open back contact I04 of relay FC. This dropping of relay FB does not drop relay E for applying the high degree of energization to the line circuit, because the last step has been taken and front contact H9 of relay 2V is on open circuit. The system remains in this condition until the train leaves the illustrated section of track, when relay T will be picked up and relay TP will be picked up because of closed front contact 20. The opening of back contacts 23 and 28 of relay TP de-energizes the stepping relays, the opening of back contact 2| of relay TP de-energizes the microphone circuit and the opening of back contact 22 of relay TP de-energizes the line circuit.

In response to the de-energization of the line, relay IF in the office is dropped and since relay '2Fis also de-energized, relay SA is dropped after a short interval-of time, The opening of front contact I and H6 of relay SA de-energizes the stepping relay circuits and the opening of front contact 103 dc-energizes the impulse relay circuits,

Code transmission.During the stepping operations at the station (Fig. 1) lamps I, 2, 3, and '4 are energized in sequence to indicate to the engineer the positions of the stepping relays in order that he may blow the whistle at any one or more of these positions. At the start of the cycle, lamp P, located in the center of the circle defined by the four indicator lamps, is energized over a circuit extending from back contact 36 of relay "1?, back contact 31 of relay 2V and lamp P to When relay 2V is picked up, this circuit for lamp P extends by way of back contact 38 of relay VP and with relays 2V and VP both picked up, the circuit for lamp P extends through front contact 39 of relay 1?.

Lamp P is therefore lighted at the start of the cycle and is extinguished, after the last step has been taken, by the dropping of relay F The purpose of lamp P is first, to indicate to the engineer that the stepping is about to begin and second, to serve the purpose of identifying the lamps by location instead of by number. This latter is useful when, due to darkness or other conditions, it is difficult to see the numbers of the lamps, they can be readily identified by their location, with respect to the center lamp P.

When the first step is taken at the station, lamp No. 1 "is lighted over a circuit extending from back-contact 36 of relay TP,'front contact 40 of relay 1V back contact 4| of relay F ,back contact 42 of relay 2V lamp I and front contact 43 of relay VP to Lamp I is extinguished when relay F picks up 'at the second step and opens back contact 4i. Lamp 2 is lighted at this step over a circuit extending from back contact'36 of relay TP, front contact 40' of relay IV front contact M of relay F back contact 44 of relay 2V1, lamp 2 and back contact '43 of relay VP to.().

Lamp 2 is extinguished at the third step when relay F drops and opens front contact M and lamp 3'is lighted at this step over a circuit extending from back contact 36 of relay TP, front'contact 40 of relay IV back contact 4| of relay F front contact 42 of relay 2V lamp 3, and back contact 43 of relay VP to Lamp 3 is extinguished at the fourth step when relay F picks up and opens back contact 4| and lamp 4 is lighted at this step over a circuit including front contacts 4! and 44 of relays F and 2V respectively, lamp 4 and front contact 43 of relay VP Lamp 4 is extinguished when relay F drops and opens its front contact 4I after the fourth step has been taken.

From the above, it will be seen that the lighting of the four stepping indicator lamps in rotation, indicates the steps being taken by the stepping mechanisms at the station and in the ofiice.

It was assumed that whistle blasts are sounded at each of these four steps. In response to the sounding of the whistle, the diaphragm of microphone MC is vibrated to alternately increase and. decrease the flow of direct current through the primary windings of transformer TF thereby inducing alternating currents in the secondary winding of this transformer of a frequency proportional to the tone of the train whistle. Thus, groups of alternating current impulses, for each whistle blast are transmitted over lines IL and 2L for impression on the input of amplifier AMP (left hand portion of Fig.2), by way of transformer TF and filter condenser C. It will be understood that condenser C in the office and condenser C at the station are for the purpose of readily transmitting these alternating current impulses without undue attenuation.

The filter comprising the inductances and condensers connected in the line conductors, is for the purpose of blocking the flow of these alternating current impulses over the circuit extending through battery LB and the line relays. Each group of alternating current impulses applied to the input of the amplifier is effective to drop relay M at each Whistle blast. When the first blast is sounded at the first step, the dropping of relay M closes a circuit for picking up pilot relay IPT extending from back contact I24 of relay M, back contact I25 of relay 2F, front contact I26 of relay E, front contact I21 of relay VP, back contact I28 of relay 2V and winding of relay IPTto Relay IPT sticks up until the end of the cycle over a circuit extending from front contact I29 of relay SA, front contact I30 and winding of relay IPT to When the whistle blast is sounded at the second step, relay 2PT is picked up over a circuit extending from back contact I24 of relay M, front contact I25 of relay 2F, front contact I3I of relay VP, front contact I32 of relay IV, back contact I33 of relay 2V, and winding of relay 2PT to Relay 2PT sticks up over an obvious circuit completed at its front contact I34.

Relay 3PT picks up at the third step, in response to the third whistle blast, over the above described circuit which now includes back contact I2'I of relay VP, and front contact I35 of relay IV. Relay 3PT sticks up over an obvious circuit completed at its front contact I36.

Relay 4PT is picked up in response to the fourth whistle blast at the fourth step, over the above described circuit including back contact I3I of relay VP, front contact I31 of relayZV and winding of relay 4PT to Relay 4PT is stuck up over an obvious circuit completed at its front contact I38.

Lamp I00 is energized, after the fourth step is taken, over a circuit extending from front contact I39 of relay FA, front contact I40 of relay VP, front contact I4I of relay 2V, front contacts I42, I43, I44 and I45 of relays IPT, 2PT, 3PT and 4PT respectively and lamp I00 to This lamp is extinguished when the stepping relays are dropped as previously described, and it will be seen that it remains lighted sufficiently long to indicate to the operator the class of the approaching train.

A pilot lamp is shown in Fig. 2 energized by the closure of front contact II6 of relay SA, for the purpose of calling the operators attention to the fact that'a train is approaching and being announced.

It is believed unnecessary to describe the operation of the system in response to other codes transmitted, since from the above explanation and the illustration of the pyramid circuits controlled by pilot relays IPT to 4PT inclusive of Fig. 2, it will be readily seen how the other lamps of the illustrated group are selected in response to these code combinations. It may be pointed out, however, that the codes in this system are built up in geometrical progression, that is, for each step added to the stepping relay banks, the number of code combinations provided is doubled.

Description of modification-In I accordance with the modification illustrated in Figs. 3 and 4, it is proposed to divide the section of track into short blocks 206, 201, 208 and 209 by'the usual insulated portions 205, for traffic assumed to be moving from left to right as indicated by the arrow. Whistle posts W are located in each of these small blocks and the engineer will blowthe whistle at any one or more of these points in accordance with the code to be transmitted. It may be found advisable in practice to provide lamps LI L2, L3 and L4, lTJcated at these whistle posts, and light them by closing circuits at front contacts 2I0, 2I I, 2I2 and 2I3 of relays ITP,.2'I'P, 3TP and 4TF as these relays are energized by the dropping of the associated track relays IT, 2T, 3T, and 4T, at back contacts 2I5, 2I6, 2" and 2 I 8, as the associated blocks become occupied.

Microphone 2MC, associated with the primary of transformer 3TF, is energized in series with choke coil ZCK from battery 2MB when any of these four blocks are occupied, by reason of the closure of front contacts 2I8, 2I9, 220 and HI.

. The occupancy of any one of these blocks energizes the line circuit, comprising line conductors ILI and 2LI,.by reason of the closure of front contacts 222, 223, 224 and 225. i

In the central ofiice, or at the point where the train indictions are to be displayed, amplifier ZAMP is inductively associated with the line circuit by means of transformer 4TF and by means of this amplifier, relay 2M is dropped in response to each whistle blast received when any one of the four blocks is occupied. Line relays 3F and 4F are connected in series with the line conductors and energized from battery 2LB, line relay 3F having its windings cumulatively effective, While the windings of relay 4F are differentially Wound so that current flowing over the line conductors in series will not pick up relay 4F.

A stepping relay bank, comprising relays 2VP, I V2, and 2V2, registers the successive occupancy of the four short blocks illustrated in Fig. 3. Pilot relays IPT2, 2PT2, 3PT2, and 4PT2 correspond to pilot relays IPT, 2PT, 3PT and 4PT, in that they are picked up at successive steps of the stepping relay bank when whistle codes are received at these steps, and although not illustrated in detail, pyramid contacts are provided on these pilot relays for selecting the 15 lamps, in the sam manner as illustrated in Fig. 2.

Although a single microphone and a single microphone transformer are illustrated in Fig. 3, it will be understood that additional microphones may be provided if desired for effectively picking up the sound waves due to the whistle blasts at the different illustrated locations.

'I'he entrance of a train into block 206 drops relay IT, which picks up relay ITP for closing the line circuit which picks up relay 3F. Line conductor 2LI is connected to ground by way of back contact 223 of relay 2TP, front contact 226 of relay ITP, and choke coil 3CK, which is effective to unbalance the line and reduce the flow of current through the lower winding of relay 4F, while increasing the flow of current through its upper winding, so that relay 4F is picked up.

With relays 3F and 4F picked up a circuit is closed for picking up relay 2VP extending from front contact 250 of relay 3F, front contact 25I of relay 4F, back contact 252 of relay 2V2, back contact 253 of relay IV2 and winding of relay 2VP to Relay 2VP closes a first stick circuit for itself at front contact 254 which is independent of front contact 25I of relay 4F.

- The entrance of the train into block 201 picks up relay 2TP and, at back contact 223, opens the above described circuit to ground which allows both windings of relay AP to be equally energized and since these windings are oppositely effective on the magnetic circuit, relay 4F is dropped.

A second stick circuit is closed for relay 2VP extending from front contact 250 of relay 3F, back contact 25! of relay 4F, front contact 255, and winding of relay 2VP to Relay W2 is picked up over a circuit extending from front contact 256 of relay 3F, back contact 251 of relay 4F, front contact 258 of relay 2VP, back contact-259 of relay 2V2, and winding of relay IV2' to Relay-1V2 closes a stick circuit for itself at its front contact 260 to at front contact256- of relay 3F.

The occupancy of block 268 picks up relay 3PT andthe line circuit is again unbalanced by connecting ground, by way of front contact 26! of relay 31? and back contact 225 of relay lTP, to line conductor 2Ll-. This effects the picking up of relay 4F which drops-relay 2VP, because its first circuit is open at back contact 253 of relay W2 and its second stick circuit is open at back contact 25| of relay 415.

The occupancy of-block 209 picks up relay dTP and 'opens the above described circuit to ground at'itsback contact225, which is effective to again balance the line and drop relay 4F. Relay 2V2 is now. picked up over a circuit extending from front contact 256 of relay 3F, back contact 251 of relay 4F, back contact 258 of relay 2VP, front contact 262 of relay 1V2 and winding of Relay 2V2 closes an obvious stick circuit for itself at its front contact 263. It will be obvious that relays ITP, 2TP, 3TP and 4T]? are de-energized' as the associated blocks become unoccupied. The dropping of all of these relays opens the line circuit and drops relay 3F, which releases the actuated stepping relays, because of open front contacts 256 and 250.

The coding of the line at each step is effected by the whistle blasts for applying alternating current energy to the line for dropping relay 2M.

Assuming that the code requires a whistle blast at each' one of the four whistle posts, relay 2M willbe dropped at each step of the stepping bank.

7 The dropping of relay 2M at the first step closes a circuit for picking up relay l PT2 extending from back contact 264 of relay 2M, front contact 265 of relay 2VP, back contact 266 of relay 2V2, back contact 261 of relay IV2 andwinding of relay=|PT2 to Since relay 3F remains upduring stepping, pilot relay IPT2 is stuck up over acircuit extending from front contact 268 of relay 3F, front contact 269 and winding of relay l PT2 to It will be-obvious that similar stick circuits for the other pilot relays are closed at their'frontcontacts 210, 2H and 212. Energy is i also applied to the stick circuits for the pilot relays at front contact 213 of relay 2V2, so that the actuated pilot relays will remain picked up until execution-takes place at the end of the cycle, as will later be described.

With alternating current energy applied to the linecircuit at the secondstep, relay 2M is dropped for picking up relay 2PT2 over a circuit including back contact 264. of relay 2M, front contact 265 ofv relay 2VP, back contact 266 of relay 2V2, front contact 2610f relay IV2, and winding of relay 2PT2 tot-e).

I-hecode applied to the line at the third step picks up relay 3PT2 over a circuit including back contact 264 of relay: 2M, back contact 265 of relay,2VP, front contact 21101 relay IV2, backcontact 215 of relay 2V2 and winding of relay 3PT2 to At the fourth step, relay 4PT2 is picked up in response to the whistle signal over a circuit including back contact 264 of relay 2M, back contact 265 of relay 2VP, front contact 214 of relay IV2, front contact 215 of relay 2V2 and winding of relay 4PT2 to When relays W2 and 2V2 are dropped out at the end of the cycle as previously described, a momentary circuit is closed for picking up executing relay EX extending from front contact 216 of relay 2V2, back contact 211 of relay I V2, and winding of relay EX to It will be obvious that, although their stick circuits are de-energi-zed at the same time, relay 2V2 will remain up longer than relay IV2 because of its slow acting characteristics.

The operation of relay EX closes a stick circuit for itself extending from closed contact 21-8 of cancelling key ICK, front contact 219 and winding of relay EX to Relay EX remains picked up until the operator de-energizes its stick circuit by actuating key ICK. The selected indicator lamp 208 is energized over a circuit extending from the right hand terminal of relay EX, by way of front contacts 286, 28!, 282, and 283 of the actuated pilot relays. The actuated pilot relays remain stuck up until key ICK' is actuated, by reason of closed front contact 289 of relay EX.

From the above description, it is believed obvious how the fifteen indicator lamps are selected by means of the whistle actuated codes applied to the line circuit in accordance with code combinations provided by blowing the whistle atom or more whistle posts illustrated in Fig. 3'.

It: will. be obvious from the above description that an executing relay and. a cancelling key could as well be provided in connection with the Fig. 2-l'circuit for maintaining the selected indicator lamp lighted until the operator actuates the cancelling key. It will furthermore be apparent that additional lamps may be selected by additional pilot relays in a system of larger capacity, by providing more short blocks similar to those illustrated in Fig. 3. It will also be understood that these indicator lamps may be arranged in groups in any desired order for indicating various classes of trains and various designations for these trains.

Repeat key RP is provided in Fig. l for the purpose of manually initiating the system. This is convenient for test purposes and of course may also be used'to cause a repeat operation of the system sothe engineer can repeat the code if desired.

Having thus shown and described a specific embodiment and one modification of the present invention, it is desired to be understood that this should not be construed as a limitation of the scope of the invention, or should it be construed as illustrating the exact construction to be em-' plo-yed in practicing the invention,"but that the specific forms illustrated have been selected for thepurpose of disclosing theprinciples and methods of practicing the invention and that various changes and additionsmay be made to adapt the invention to particular problems encountered in practice, all without departing from the spirit thereof, except as limited by the scope of the appended calims;

What I claim is:.

- 1. In combination, a plurality of indicators at one location selectively operated in response to a train whistle at a distant location, a step by step mechanism at said one location, line wires interconnecting said locations, means for operating said mechanism to prepare channel circuits, and means controlled over said line wires for energizing the channel circuits for selecting and operating said indicators in accordance with codes made up of the presence and absence of whistle blasts at the various steps of said mechanism.

2. In combination, a plurality of indicators at one location selectively operated in response to a train whistle at a distant location, a step by step mechanism at said one location, line wires inter-connecting said locations, means controlled over said line wires for operating said mechanism to prepare channel circuits, and means controlled over said line wires for energizing the channel circuits for selecting and operating said indicators in accordance with codes made up of the presence and absence of whistle blasts at the various steps of said mechanism.

3. In combination, a plurality of indicators at one location selectively operated in response to a train whistle, a step by step mechanism at said one location and a step by step mechanism at another location, line wires inter-connecting said locations, means for operating said mechanisms in synchronism to energize signals at said other location and to prepare channel circuits at said one location, and means controlled over said line wires for energizing the channel circuits for selecting and operating said indicators in accordance with codes made up of the presence and absence of whistle blasts sounded at the various steps of said mechanisms as identified by said signals.

4. In combination, a plurality of indicators at one location selectively operated in response to a train whistle, a step by step mechanism at said one location and a step by step mechanism at another location, line wires inter-connecting said locations, means controlled over said line wires for operating said mechanisms in synchronism to energize signals at said other location and prepare channel circuits at said one location, and means controlled over said line wires for energizing the channel circuits for selecting and operating said indicators in accordance with codes made up of the presence and absence of whistle blasts at the various steps of said mechanisms as identified by said signals.

5. In combination, a plurality of indicators at one location selectively operated in response to a train whistle, a step by step mechanism at said one location and a step by step mechanism at a distant location, line wires inter-connecting said locations, means for operating said mechanisms in synchronism to select signals at the distant location and prepare circuits at said one location, means including the step by step mechanism at said one location controlled over said line wires and responsive to whistle blasts at certain steps of the step by step mechanism at said distant locations for energizing the circuits for selecting and operating said indicators, said signals indicating the-various steps taken by the step by step mechanism at said distant location.

6. In combination, a plurality of indicators at one location selectively operated in response to a train whistle, a step by step mechanism at said one location and a step by step mechanism at a tant location and for preparing circuits at the one location, means including the step by step mechanism at said one location controlled over said line wires and responsive to whistle blasts at certain steps of the step by step mechanism at said distant location for selecting and operating said indicators, said signals being lamps sequentially lighted at the separate steps of the step by step mechanism at said distant location.

7. In combination, a stretch of railway track, a plurality of train class indicators, a microphone located adjacent the trackway and operated by blasts from a train whistle comprising a code, code responsive means, means for selecting said code responsive means, means controlled by said microphone for operating the selected code responsive means, means controlled by said code responsive means for selecting said indicators, visual means located adjacent said trackway and operated in synchronism with the selection of said code responsive means for indicat'- ing that a code responsive means is prepared for operation by the microphone controlled means, and means for energizing the selected indicators.

8. In combination, a stretch of railway track divided into a plurality of blocks, a plurality of train class indicators, a microphone located adjacent the trackway and operated by blasts from a train whistle comprising a code, a separate track circuit for each of said blocks, code responsive means, means controlled by said track circuits for selecting said code responsive means, means controlled by said microphone for operating the selected code responsive means, means.

controlled by said code responsive means for selecting said indicators, and means for ener-' gizing the selected indicators.

9. In combination, a stretch of railway track at one location divided into a plurality of blocks,

a plurality of train class indicators at a distant location, line wires connecting said locations, a

microphone located adjacent thetrackway and controlled by said code responsive means "for selecting said indicators, and means for energizing the selected indicators.

10. In a'train describer system, a first location at which classes of trains are to be indicated, a second location where said trains pass, a line circuit inter-connecting said locations,'step by step mechanisms at said locations operated in synchronism by a series of direct current impulses applied to said line circuit for energizing signals at the second location and for preparing circuits at the first location, means controlled by a train at said second location for effecting the application of said direct current impulses to said line circuit, train controlledmeans' for selectively applying alternating current impulses to saidline circuit at any one or more steps'of said mechanisms as identified by said signals, and

train indication means at said first location se-' lectively responsive, through the channel circuits, to alternating current impulses selectively applied to said line circuit.

11. In a train describer system, a first location at which classes of trains are to be indicated, a second location where said trains pass, a line circuit inter-connecting said locations, step by step mechanisms at said locations operated in synchronism by a series of direct ourrentimpulses applied to said line circuit, means controlled by a train at said second location for effecting the application of said direct current impulses to said line circuit, train controlled means for selectively app-lying alternating current impulses to said line circuit at any one or more steps-of said mechanism, train indication means at said'firstlocation selectively responsive to alternating current impulses selectively applied to said line circuit, and a visual indicator at said second location distinctively operated at each step of the associated step-by-step mechanism for indicating when said alternating current impulses are to be applied to said line circuit. l

12. In a train announcing system; a first location at which a plurality of trains of different classes are to be announced; a second location where said trains pass;a line circuit connecting said locations; a step-by-step mechanism at said first location operated through a predetermined number of steps in synchronism with a series of direct current impulses applied to said line circuit; train controlled means at said second location for'eifecting the application of said direct current impulses to said line circuit; train controlled means at 'saidsecond location for selectively applying alternating current to said line circuit at any step of said mechanism; a plurality of pilot relays at said first location, one being picked up or left down at each step taken by said mechanism dependent upon whether or not alternating current is applied to said line circuit at that step; a plurality of indicator lamps, each having a selecting circuit through said plurality ofpilot relays; 'the greatest number of different selections for any one number of said pilot relays being tworaised to the power of the number of pilot relays, whereby only one particular indicator lamp is selected for any one series of direct current'impulses applied to said line circuit; and means for energizing any selected'indicator lamp.

13. In a train announcing system; a first location at which a plurality of trains of different classes are to be announced; a second location where said trains pass; a line circuit connecting said locations; a step-by-step mechanism at said first location operated through a predetermined number of steps in synchronism with a series of direct current impulses applied to said line circuit; train controlled means at said second location for efiecting the application of said direct current impulses to said line circuit; train controlled means at said second location for selectively applying alternating current to said line circuit at any step of said mechanism; a plurality of pilot relays at said first location, one being picked up or left down at each step taken by said mechanism dependent upon whether or not alternating current is applied to said line circuit at that step; a plurality of indicator lamps, each having a selecting circuit through said plurality of pilot relays; the greatest number of different selections for any one number of said pilot relays being two raised by the power of the number of pilot relays, whereby only one particular indicator lamp is selected for any one series of direct current impulses applied to said line circuit; means for energizing any selected indicator lamp; and a stick circuit for each pilot relay including 7 its own front contact and a contact 'opened only at the end of said predetermined number of steps. v

14. In atrain announcing system; a first location at which a plurality of trains of different classes are to be announced; a second location where said trains pass; a line circuit connecting said-locations; a step-by-step mechanism at said first location operated through a predetermined number of steps in synchronism with a series of direct current impulses applied to' said line circuit; train controlled means at'said second location for efiecting the application of said direct current impulses to said line circuit; train controlled means at said second location for selectively applying alternating current to said line circuit at any step of said mechanism; a plurality of pilot relays at said first location, one being picked or left down at each step taken by said mechanism'dependent upon whether or not alternating'curr'ent is applied to said line circuit at that'step; a plurality of indicator lamps, each having a selecting circuit through said plurality of pilot relays; the greatestnumber of diiierent selections for any one number of said pilot relays being two raised to the power of the number of pilot relays, whereby only one particular indicator lamp is selected for any one series of direct current impulses applied to said line circuit; means for energizing any selected'indicator lamp; and a stick cir'cuit'for each pilot relay including its own front contact and a contact opened only in response to the operation of a manually operated key.

15. In combination, a train indicator operated by codes comprised of groups of sound waves emitted by a train, a cyclically operated indicator for indicating when said groups of sound waves shall be emitted to make up said codes, code registering means for registering said groups of sound waves, and means controlled by said code registering means for selectively operating said train indicator in accordance with said codes.

16. In a train announcing system in which code signals are transmitted over a line circuit from a station to a central oifice for indicating train classes, a train class: indicator in said central office, means for applying an invariable number of time spaced impulses of direct current to said line circuit, means for creating said code signals by superimposing a variable number of groups of alternating current impulses on said line circuit in synchronism with selected ones of said direct current impulses, and means controlled by said code signals for selectively operating said train class indicator.

17. In a train announcing system in which code signals are transmitted over a line circuit from a station to a central office for indicating train classes, a train class indicator in said central oifice, means for applying an invariable number of time spaced impulses of direct current to said line circuit, means for creating said code signals by superimposing a variable number of groups of alternating current impulses on said line circuit in synchronism with selected ones of said direct current impulses and the time spaces between said direct current impulses, and means controlled by said code signals for selectively operating said train class indicator.

18. In a train announcing system in which code signals are transmitted over a line circuit from a station to a central oifice for indicating train classes, a train class indicator in said central office, means for applying an invariable number of time spaced impulses of direct current to said line circuit, means for creating said code signals by superimposing a variable number of groups of alternating current impulses on said line circuit in synchronism with selected ones of said direct current impulses, means controlled by said code signals for selectively operating said train class indicator, and means for visually indicating when said direct current impulses are applied to said line circuit.

19. In a train announcing system, in combination, a central ofiice and a remote location, means for transmitting an invariable number of impulses of direct current over a line circuit internecting the remote location with the central office, visual means at the remote location controlled by the direct current impulses over the line circuit for indicating the transmission of said direct current impulses, and means for'selectively operating an indicator in said omce by codes made up by applying or not applying alternating current impulses to said line circuit as the transmission of each of said direct current impulses is visually indicated.

20. In a train announcing system, in combina tion, a central oifice and a remote location, means for transmitting an invariable number of impulses of direct current over a line circuit interconnecting the remote location with the central oflice, visual means at the remote location controlled by the direct current impulses over the line circuit for indicating the transmission of said direct current impulses, and means for selectively operating an indicator in said office by codes made up by applying or not applying alternating current impulses to said line circuit in response to the presence or absence of whistle blasts, as the transmission of each of said direct current impulses is visually indicated.

21. In combination, a train indicator operated by codes comprised of groups of sound waves emitted by a train, an indicator for indicating when said groups of sound waves shall be emitted to make up said codes, time controlled means for controlling said indicator, code registering means for registering said groups of sound waves, and means controlled by said code registering means for selectively operating said train indicator in accordance with said codes.

22. In combination, a train indicator operated by codes comprised of groups of sound waves emitted by a train, an indicator for indicating when said groups of sound waves shall be emitted to make up said codes, means controlled in accordance with the position of the train on the track for controlling said indicator, code registering means for registering said groups of sound waves, and means controlled by said code registering means for selectively operating said train indicator in accordance with said codes.

WINFRED 'r. POWELL.

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