US2193292A - Continuous train control and signal system - Google Patents

Description

March 12, 19 0. J. c. M DONALD CONTINUOUS TRAIN CONTROL AND SIGNAL SYSTEM 2 Sheets-Sheet 1 Filed Feb. 10, 1939 Arw AMPL/F/E'R IJO v SIG/VAL CAUT/a SECTION] 100- axe/VAL a INVENTOR. /vv 6, mc omfd,

ATTORNEY BY I I March 12, 1940. C IMCDONALD 2,193,292

CONTINUOUS TRAIN CONTRQL AND SIGNAL SYSTEM Filed Feb. 10, 1939 2 Sheets-Sheet 2 60- SIG/VAL AMPLIFIER I N V EN TOR. 06w (9. muflamw,

J BY

ATTORNEY.

Patented Mar. 12, 1940 i 2,193,292 CONTINUOUS TRAIN CONTROL AND SIGNAL SYS J ohn C. McDonald, Annsville, near Peekskill, N. Y. Application February 10, .1939, Serial No. 255,732

13 Claims.

My invention relates broadly to railway block systems and moreparticularly to a continuous train control and signal system adapted for modcm high. speed operation.

This application is a continuation-in-part of my copending application Serial No. 190,121,fi1ed February 11, 1938, and allowed December 23, 1938, for Railway blocksystem and power supply circuit. l

simplified form whichis relatively inexpensive to install and maintain but which has a high factor of safety and reliability. i

Another object of my invention is to provide a train control and signalsystem for high speed train operationwherein longer track sections may be employed and signals and control energy transmitted to thetrain continuously throughout the track sections.

Still another object of my invention is to provide a block signal and control system of uniform arrangement in each block section and without connection between the ends of a track section except through the track rails. l

A further object of my invention is to provide a continuous train control and signal system wherein multi-frequency currents in the track rails are separately employed for signal and control purposes and wherein the presence of a train in a track section effectsthe application of the proper frequencycurrent.

A still further object of my invention isto provide a train control and signal system having the track rails supplied normally with energizing current, with means operative upon the entrance of a train into the section to removesuch current and substitute one or another of different currents indicative of track conditions in the forward section, the train being controlled accordingly) I Still another object of my invention is to provide an intermediate connection to a track section in arailway block signal and control system whereby a sufiicient track: length adjacent the exit of the section is provided for stopping a train in the event the forward section has not been cleared at the time the following train reaches the intermediate control connection.

A further object of my'invention is to provide emergency brake control means operative automatically to stop a train under predetermined unsafe track conditions, and manually controlled means for releasing the brakes for restarting the train, the releasing means being operable only Oneof the objectsof myinvention is to provide a a continuous train control and signal system of i ciated with the trainat rest and having associated therewith a mechanical counter for registering the operation of the releasing means; also, in this connection, it is an object of my invention to provide speed governingmeans effective when. 5

the train is running by virtue of the manually operated brake releasing means.

I ,Another object of my invention is to provide speed control means operative in lieu of positive braking means Where the'operation of the brakingmeans is prevented or nullified in thediscretion of the engineman, such as when it is desired to proceed under a caution signal, or when it isnecessary to approach close to another train to render assistance or the like.

Other and further objects of my invention rea side in the circuit arrangements and apparatus herein disclosed aswill be understood from the description thereof hereinafter set forth with reference to the accompanyingdrawings in which:- 2 Fig. l is a schematic diagram of the system ofmy invention, showing the track circuitsassowith a representative track length and the cab circuits and apparatus aboard the. train, in

v a preferred arrangement; Fig. 2 is a schematic diagram of a modified form of track circuit showing two different frequency supply circuits instead of the three indicated in Fig. 1; Fig. 3 is a schematic diagram of a modified form of cab circuit with separate speed control provisions for conditions requiring caution; and Figs. 4 and 4A are diagrammatic illustrations of one form of speedometer dial and indicator vane cooperative with photoelectric devices in the speed control systems of my invention.

Developments in the structural and operational aspects of railway .trains in late years have createdthe need for more adequate and more positively operable signaland control systems. A primary consideration, due to the increased speeds of travel, isthe lengthening of the track section in the usual block system while stillmaintaining reasonable voltage and current facilities for the signal system. I have devised for the purposes of supplying the required current values and providing for the variation thereof in operation a new form of power supply circuit shown and claimed in mylcopendin'g application Serial No. 190,121, supra; This form of supply circuit is employed in the system herein disclosed. p

Another consideration of vital importance is the provision of adequate signal and control devices aboard the train positively operable throughout the extended track sections. Cab

signals heretofore employed have required elaborate and expensive equipment diflicult to maintain and therefore of doubtful reliance. In the system of my invention, by virtue of the incorporation of the novel power supply circuit and other characteristic features, the cab signals are continuously operated and the control circuits energized with a minimum of equipment, few moving parts and in a positive and reliable manner. The simplicity and reliability of the system of my invention therefore contribute to a high safety factor, and this combined with the relative inexpensiveness and low maintenance costs involved constitute the practical features which characterize the system of my invention.

Referring to the drawings in detail, the lower portion of Fig. 1 represents the wayside track circuits whereas the upper portion, boxed by broken line I, shows the cab circuits and the apparatus carried by the train. The broken line 2 encloses apparatus which is located at one position adjacent thejunction of two track sections, at the wayside. Portions of three track sections are indicated in Fig. 1, with the train moving in the direction of arrow 3-through sections III, II and I, consecutively. The condition of the circuits shown is that wherein section I isunoccupied and forward of section II which is occupied by a train one set of wheels of which is indicated at 4.

Section II is supplied with current at one of three frequencies through transformer arrangements of the type disclosed in my copending application Serial No, 190,121, supra. A 60 cycle source is-connected with a transformer system including transformers 5 and 6 both of the same ratio of turns, e. g. 12:1. Primary 5a is connected directly across the 60 cycle source .whereas primary 6a is connected through the rails and across the source. The circuit of primary 6a is normally completed through relay winding I con- 'nected with therails of section II at the far end thereof, but in the condition shown, the wheels 4 shunt the relay 1 so that primary 60. receives substantiallythe same voltage as primary 5a, and in the same phase, and substantially no power current flows in the'shunted rails. secondaries 5b and 619 are connected together with their voltages in phase opposition so that with the ratios of transformation equal, as prescribed, no current flows in the loop circuit including the secondaries 5b, 6b.

' A similar loop circuit comprising separate secondaries 5c, 60, is provided for energizing a relay II by a current produced in the loop circuit by virtue of phase shift in the voltage supplied to primary 6a when relay winding I is energized, which winding is inductive. The relay I I is thus responsive, as is relay 1, to the presence of a train in the section. Relay I, connected with section I is shown energized in accordance with the clear track condition assumed, whereas relay I connected with section II is deenergizedl. The purpose of the separate loop circuit 50, 6c, is to supply adequate current to the relay II without circuit to the transformer group I4, I5, of which transformer I4 has a higher ratio of turns than does transformer I5, e. g. a ratio of 60:1 in transformer I4 and a ratio of 12:1 in transformer I5. Primary I Ia is connected directly across the source, which may be of cycle frequency, whereas primary 15a is connected to the 100 cycle source through the rails of section II and contacts Ia of relay I, which are closed under the condition shown. secondaries I41) and I5!) are connected together with their voltages in phase opposition, but as the ratios of transformation are unequal current flows in the loop circuit and counter voltage is produced in primary I5a. which reduces the line voltage applicable to the rails. This counter voltage is functional also resulting in decreased in-phase counter voltage.

The voltage applied to the rails therefore automatically decreases as the resistance of the rails is shunted, by virtue of increased counter voltage in the transformer I5, making the current substantially uniform, independent of the length of the track section. i H

It will be seen that as the current of 100 cycle frequency is applied to the rails of section II with section I clear in the condition shown,.this frequency is indicative of clear track conditions.

Relay contacts I2b and I2c upon closing complete a circuit to the transformer group. I6, 11, similar in connection, constitutionand operation .to the group I4, I5; thus, transformer I6 has a ratio, for example, of 60: 1 and transformer II a ratio of 12: 1. .Current from the group I6, [1, is applicable to the rails of section II through relay contacts 11) and 10', shown open. These contacts are closed: when relay I is deenergized-as by section I being occupied, by a broken rail in section I or any similar hindranceto clear runningand the current in this instance, which may be of -cycle frequency, is employed t indicate that caution is required.

This 150 cycle current is applied to the rails of section II at a predetermined distance from the exit end of the section, a distance of four hundred feet being suggested by way of example. This provision will be more fully considered in connection with the operation of the cab circuits at I, but in general the distance represents the space required to bring the train to a stop from a governed low speed at which the train may be running, in the event a track clear signal is not produced before the point of connection of the 150 cycle current is reached. In this portion of the track section II, there is substantially no power current in the rails when section I is occupied, which is indicative of danger conditions and the train is brought to an emergency stop, as will be explained. Similarly, complete failure of the control system due to any cause, natural or accidental, resulting in the absence of any current in the rails, will produce the indication of danger with the train anywhere in the section, and the local cab circuits will operate to apply emergency brakes.

The purpose of'relay contacts I20 is to open the shunt circuit that would otherwise stand across the rails of section II when section I is occupied but section II is not. That is, the primaries of transformers I6 and II, are connected inseries with contacts I20 with respect to the transformer bank 5,,6, through the rails, and contacts I20 are closed by relay IE only when section II is occupied.

It will be understood'that the frequencies 60,

L00 and 150 cycles are merely suggestive and the presence of a train in section I-by-shunting relay 1" andthus the 150 cycle current, indicating caution, is applied to the rails. This means of control is applicable where cautionis required for various reasons such as roadbed repair, curves, crossings, townships, etc. The relay 1% isof a type which operates for a limited time .period so that the control afforded thereby may be regulated to the particular portion of the track section considered; such a relay may be constructed in accordance with Albert B. Rypinski Patent 2,082,121, granted June 1, 1937, for.Slow electromagnet. If the condition requiring caution is temporary, or is subsequently remedied, the relay l8 may be removed from the system, asin Fig.2."

Referring now to the cab circuits shown at i in Fig. 1, coupling to the rails is eiTected by means of coils l9 and which have voltages induced therein by the current in the rails. The coils i9 and 20 areconnected to an amplifier 2!, which may be of the electron tube type, and the output thereof is used to drive a motor 22 at speeds proportionalto the frequency of the current in the rails. A single phase, four pole motor will have a speed of 3000 R. P. M. fed with 100 cycle current, and a speed of 4500 R. P. M. fed with a l50 cycle current. The motor 22 drives shaft 23 which has a centrifugal device such as the fly- .ball arrangement shown at 2t connected therer with. Reciprocable rod 25 is actuatedbythe centrifugal fly-ball device according to the position of the weights in the device as determined by the speed of rotation of shaft 23, controlled by the signal frequency. Rod 25 is provided with lug 25a which is disposed in operative relation to two tongue switches 26 and 2']; switch 26-is closed by theaction of. lug 25a when the speed of the motor 22 is low, say 3000 R. P. M., which corresponds to the signal of clear track condition, as shown. At 4500 R. P. l/Lof motor 22, lug 25a acts to close the contacts of switch 27 pursuant to the application of 150 cycle current to the rails, indicating that caution is required.

. With motor 22 at rest, lug 25a moves beyond switch 2% and both switches 25? and 21 are left open, the cab circuits then indicating danger conditions.

' An independent power source is provided at 28 for the cab apparatus with connector buses 29 and 30. A relay 3i is connected from bus 30 through switch 2% to bus v29, and is shown energized-inaccordance with assumed confitions.

Relaycontacjts 3 la complete a circuit from bus 29 through lamp 32 to bus 30, lamp 32 giving a green signal indicative of clear track conditions. A relay 33 is connected from bus 30 to switch 2'! and thereby to bus 29; relay 33 is thus operable when relay 3| is deenergized whereupon a circuit is completed from bus 29 through relay contacts 311) and 33a to lamp 34 and bus 30, lamp 34 being colored yellow to indicate caution. A relay 35 is connected with bus 30 and controlled by relay equivalent to the relay vices above set forth contacts 33band 3! b in connection to bus 29 so that relay 35. and 33 are deenergized. Relaycontacts 35a complete a circuit from bus 29 to lamp 36 and bus 30, lamp 30 being colored red to indicate danger conditions; this circuit relation. obtains normally in the cab circuits when motor 22 is at rest, caution and clear signals under which the train may be operated being derived only from positive indications afforded by current in the track rails. Relay 35 is deenergized in such case upon the operation of either relaySi or 33. i

Accompanying the operation of the signal deare certain automatic con- Under clear track conditions and with the green lamp 32 illuminated, brake control valves 3'! and 38 are both closed. These valves are .electromagnetically"controlled, as introl functions.

dicated, and valve 31 which controls theemercuit thereto is incomplete at relay contacts 3lc. Relay 3Q which controls contacts 3% is operable pursuant to caution conditions as will now be' considered. g l v When lug 25a leaves switch 20 and moves to actuate switch 27 under control of motor 22, relay 3! is deenergized and relay 33 is energized, the latter closing a contacts 330, upper contacts lilaof a manual switch 40, andvalve coil 3% to bus 30, thus opening valve 38 and makingservice application of the brakes to slow the trainto a cautious speed, ultimately effective to stop the train should the caution signal not be removed. "The application of the brakesby opening valve 38 may be precluded by operation of the manual switch it by the engineman, thus closing contacts tub by which relay 39 is energized instead of valve coil 38a. By this operation, a speedgoverning system is brought into use associated with a. speedometer device having vanetl operated thereby and'adapted to control a photoelectric relay for operation above the predetermined safe speed. The relay includes light source 42 and photocell 63, with vane 4i movable therebetween and arranged to expose the cell Q3 to the light source above a certain speed designation, say 30 M. P. H. The photocell 43 is in circuit-from bus 3& with a relay 44 and relay contacts 33d-which latter are closed when relay 33 is energized-and relay contacts' 3ic tobus 29. It will be remembered that relay 39 is energized through contacts ltib when it is desired to prevent service application of brakes through valve 38; relay contacts 3% thereby being opened, valve- 31 would open for emergency application of the brakes were it not for a shunt circuit through contacts 452) of a relay 45-from valve coil 37a to bus 29. This shunt circuit is dependent upon energization of relay 45 which in turn depends of relay 44, .a condition obtaining with maintenance of safe speed under the caution signal. Exceeding the predetermined speed causes vane upon deenergization is energized when both relays 3| service application of the valve 38 is closed as the circircuit from bus 29 through relay restorationof the clear track signal removes all restrictions by deenergizing relay 33 at switch 21,

, ber of times which opens the circuit to valve coil 38a at contacts 33c, and simultaneously releases relay 39, at contacts 330, which restores the circuit for valve coil 31w at contacts 39a.

Considering now the danger conditions indicated by absence of current for motor 22 and opening of both switches 26 and 27, leaving relays 3! and 33 deenergized. A circuit is established to relay 35 from bus 29 through contacts 3H) and 33b, returning to bus 38, as heretofore set forth. The closing of relay 35 immediately opens the circuit to valve coil 31a at contacts 35b and the train is brought to an emergency stop;

1 the engineman cannot prevent this occurrence by any means within his control whilerunning the engine. However, as it is often necessary to approach close to a forward train despite the danger signal, means are provided whereby the brakes may be released and the train may proceed; in such case, record is made of the release of the brakes and the speed control hereinbefore described is effective after restarting the train.

In order to release the brakes, relay 45 is operatedby push button switch 46 which completes a circuit from bus 3i], through control contacts 44w, switch 46, relay 45, relay contacts 33c and 3 I0 to bus 29; relay contacts 45a shunt the push button switch 46 and hold the circuit closed. Switch 46 may be positioned exterior of the cab so that it is' impossible 'to reach it while the train is running, making it necessary for the engineman to leave the cab and consciously operate the switch; a mechanical register of the numthe switch is operated is provided at 4"! in cooperable relation thereto in order that a check may be made on the enginemans actions in respect thereto. 1

Operation of relay 45 closes contacts 45b and restores current to valve coil 38a. and releases the brakes. With relay 35 also energized, contacts 350 complete a circuit frombus 29 through relay 44 to photocell 43 and bus 3D, rendering the photoelectric relay operative to control contacts 44a and thereby relay 45 and contacts 45b in circuit with the valve coil 31a, so that excessive speed results again in the emergency application of the brakes, upon the opening of contacts 45b. In the modified forms of my invention shown in Figs. 2 and 3, the operation is generally similar to that of Fig. 1. Fig. 2 illustrates a form of track circuit in which two instead of three sources of different frequency current may be employed in the. track circuits with the same results achieved and no modification of the cab circuits required. The 60 cycle current, it will benoted, is present in the rails in the system c" Fig. 1 only when the section is unoccupied, the same being reduced to substantially zero by the shunt on the rails provided by a train in the section; any current of 60 cycle frequency that may be detected in the rails in such instance is wattless, of substantially zero power factor, and incapable of transmitting a signal to the coupling coils I9 and 20. This condition is attributable to the transformer connections in the 60 cycle power supply and especially the equal ratio of transformation in the two transformers 5 and 6.

Now, in Fig. 2, I provide connections from the 60 cycle source to another of the transformer systems, the former cycle system, the output whereof under proper circuit conditions includes a 60 cycle power component which is fed as a signal current to the rails in place of the 100 cycle current provided in Fig. 1. There is no conflict of effect between the wattless current from the transformers 5, 6, and the signal current from transformers I4, I5, even though they are of the same frequency. Transformers I4 and I5 are of different ratio and the ouput thereof through the rails and the train shunt 4 has a definite power factor, between zero and unity, and is thus capable of transmitting a signal to the cab circuits whereas the wattless output of the equal ratio transformers 5 and 6 is not. The absence of current both from transformers I6 and I1 and from transformers I4 and I5 in any portion of an occupied section is still indicative of danger conditions, and efiective thus in the cab circuits, despite the presence of current of the frequency of one of the signal currents from transformers 5 and 6 as this current is essen tially impotent as it draws substantially no power from the power source. The economical advantages of this modified form of track circuit should be evident.

In the modified cab circuits shown in Fig. 3, I provide an auxiliary speed control system operative with respect to the service brake control valve 38 for running under caution indications. This arrangement is adequate for maintaining the speed of the train below a predetermined rate without involving the extreme condition of application of emergency brakes and without entailing the delays accompanying the operation of the emergency brakes where the speed may have but momentarily exceeded the limit. Another advantage of this form of circuit is that different speed limits may be invoked for operation under caution and under danger signals; the limit for the danger conditions may then be set very low and that for caution conditions reasonably greater. I

The specific auxiliary speed control system is connected with contacts 45b on the manual switch 40 and comprises. contacts 480. controlled by relay 48 in circuit with photoelectric regulating means similar to that at 4I-43 connected with relay 44. The auxiliary photoelectric means comprises light source 49, speedometer vane 55 and photocell 5i. The cell- 5I is constantly energized by the circuit from bus 30 through the cell 5I an relay 48 to bus 29 and is thus conditionedfor immediate operation.

Upon receiving the caution signal relay 33 is energized, as hereinbefore explained, and valve coil 38a is energized through circuit 330' to apply the service brakes. This action is forestalled by manual operation of switch 45 which puts contacts 48 in circuit with the valve coil 38a and the service brake is then under control of the speedometer vane 50 which allows the photocell 5| to be activated by light from lamp 49 whenever the train speed is above the limit.

In such instances relay 48 is energized and con- -Thespeedometer vane 50 and that at 4| are constructed in the general form indicated in Fig. 4 at 52 which includes a radial portion 52a with indicator 52b movable along the scale 53a on dial jects through the opening 54 and is effective on] the photocell when the opening is uncovered as shown in Fig. 4A. Thus, the photocells 5| and 43 may be operated when the train reaches any predetermined speed, by proper disposition of the opening '54 on the dial and cooperativedesign of ,the circumferential arm 52's, and the cells remain operated for all speeds above the selected limit.

, Preferably a separate shutter arm 520 ispro vided for eachphotocell system, and thesemay be radially-or circumferentially displaced. Also,

it will be understood, any equivalent form of speed responsive circuit control, element maybe employed in lieu of the photoelectricrelay, system shown; andmodifications may bemade as well in the arrangement shown inFig'. 4; such as to cut ofi the light at a certain speed, with alterationsin the immediate relay' corresponding circuits. I

In Fig. 3, the modifications made involve the elimination of relay 39 and associated circuits VI and resultin great simplification of operations The'rem ainder of the cab circuits will bereadily understood from the description hereinbefore given in respect to similar circuits in Fig.1, with theuexception that ,contacts 39a are replaced by a direct conneotion from contacts b't0 valve coil 31a.

The system of my invention is applicable to track sections of 12,000 foot length for speeds approximating 125 miles per hour, and may be em-n ployed also with sections of approximately 20,000 foot length where speeds of about 140 miles perhour can be attained with'reliance upon clear track conditions ahead. The operation of the train is within the complete control of the engineman only with clear track indicated as at all other times positive braking is, applied or the train is proceeding under a speed control the violation of which results in application of brakes.

Moreover, each timethe train is restarted after an emergency stop, a record is made which cannot be circumvented or contradicted and for which the engineman will be held accountable While I have described my invention in certain preferred and modified forms, I am aware that various further modifications may be made in means and circuit connections withinthescope of my invention, and Idesire it understood that no limitations upon my invention are intended except as are imposed by the appended claims.

What I claim as new and desire to secure by Letters Patent of the United Statesis as follows: 1. A continuous train control and signal syn,- tern comprising a plurality of insulated rail track sections, ,means for, selectively supplying elec:

trical energy at a certain frequencyto thewhole cf eachtrack section under safe track conditions in advance of the respective track section,

meansfor selectively supplying electrical en rgy at a different certain frequency to a limited por-' tion of each track section extending from;the

entrance end thereof under advance traflic and track conditions requiring caution in the respective track section, energy of both said frequenc'ies being absent under unsafe traffic and track conditions in advance of the respective track section, and signal means carried by a train operative over said track sections selectively responsiveto the frequency of the energy'in the rails of any track section, the last said means being responsive to the frequency indicating caution within said limited portion of the track section and operable for the remainder thereof i in accordance with safeorunsafe conditions.

2. A continuous trail control and signal system includinga plurality of insulated'rail track sections, track relay connected to the rails of each track section, means for supplying electrical control energy to the rails in each track section to control the respective track relay, means for supplying electrical signal energy ,to the rails of each track section to control train, carried apparatus, andmeans responsive to a-change. of

current in the said control: energy supplying means uponthe entrance of -a train, in the respective section and connected with the saidsignal energy supplying means in the same-sec tion for energizing the saidsignal energy supplying means and supplying signal energy to the rails of the respective section. 3. A continuous traincontrol and signal system asset forth in claim 2 with each track relay connected with the rails at the entrance to the respective track section, the track relay con- I nected to a first ofsaid plurality of track sections being operative in accordance with the control energy supplied thereto, said track relay having control contacts connected with the means forsupplying signal energy to a second of said plurality of track sections adjacent the entrance end of the said first track section for controlling the applicationof signal 'energy'to the said second track section in accordance with track conditions in the said first track section.

4 A continuoustrain control and signal system including a plurality of insulated rail track sections, means for supplying electrical control energy for wayside apparatus to the rails in each track section, means for supplyingelectrical signal energy for train carried apparatus to the rails in each track section, and automatic, switch means responsiveto a change of current in the said control energy supplying means upon the entrance of a: train in the respective track section and connected with the said signal energy:

supplyingmeans for energizing the said signal energy supplying means and supplying signal energy to therails of the respective section.

,5. A continuous train control and-signal system as set iorth in claim 4 and including a track relay connected, with the rails at the entrance of an advance track section and having control contacts'connected with the said signal energy supplying meansconnected with'the next rearward track section for controlling the application of signal energy 'to the next rearward respective track section, in accordance with traific conditions. in the advance track section, and means, operative in conjunction with the said automatic switch meansand connected with said track relay for determiningthe operation of said track relay independently of advance trackconditions, 6. A continuous train control and signal sys-.

tem including a plurality of insulated rail track sections, a trackrelay connectedto the rails of each track section; means for supplying electrical control energy to the rails in each track section to control the respective track relay comprising a source of alternating current control energy, a pair of transformers of the same ratio of transformation having secondary windingswith terminals of like polarity connected together and primary windings connected across said source with the rails of the respective track section and said track relay in series with one of said primary windings; means for supplying electrical signal energy to the rails in each track section to control train cab signals comprising a source of alternating current signal energy, a pair of transformers of unequal ratios of transformation having secondary windings with terminals of like polarity connected together and primary windings connected across said source with the rails of the respective track section and said track relay in series with one of said primary windings; the power out,-

put from said control energy supplying means and fromsaid signal energy supplying means to the rails of the respective track section being functional upon the phase of the currents in the primary windings in each of said means and upon the ratio of transformation in the interconnected transformers, the shunting of the rails of the respective track section and of the track relay connected with the rails by a train in said section producing substantially zero phase differences in the primary currents in each of said means whereby the power output of the said control energy supplying means is substantially zero and the power output of the said signal energy supplying means is dependent upon the diiference in the ratios of transformation in the pair of transformers therein; and means responsive to a change of current in the said control energy supplying means upon the entrance of a train in the respective track section and connected with the signal energy supplying said means for initiating the operation of the signal energy supplying means.

'7. A continuous train control and signalsystem as setforth in claim 6' wherein said source of control energy and said source of signal energy are of the same frequency, and wherein said means for supplying control energyto the rails produces wattless current at the common frequency while said means for supplying signal energy produces power current at the common frequency in the rails of an occupied track section; and including a common prime source of power of the said common frequency connected with both the aforesaid sources of energy for supplying power thereto.

8. A continuous train control and signal system as set forth in claim 6 and including separate prime sources of power at diiferentfrequencies connectedrespectively with said source of control energy and said source of signal energy for supplying power thereto.

9. A continuous train control and signal system including a plurality of insulated'rail track sec-' tions, a track relay connected to the railsin each track section; means for supplying electricalcontrol energy to the rails in each track section to control the respective track relay, said means having a power output functional upon the phase of the current supplied to the rails in the respective track section, said power output being substantially zero in the rails of an occupied section; means for supplying electrical signal energy to the rails in each track section to control train cab signals; and means responsive to a change of current in the said control energy pp y ng energy, a pair of transformers each having primary and secondary windings and constituted with different ratios of transformation, connections from one of said primary windings directly to said source, connections from the other of said primary windings to said source through the rails of the railway block system, and connections be! tween terminals of like polarity on said secondary windings, the voltage supplied to said rails being proportioned to the length of the track in circuit with the second said primary winding and dependent upon the difference in said ratios of transformation.

11. A continuous train control and signal system comprising a plurality of insulated rail track sections, means for supplying current of different signal frequencies to the rails of an occupied track section in accordance with track conditions in advance of said section, selective control means carried by a train in said track section responsive to the different signal frequencies of current in the rails, signal means actuated by said selective control means in response to one signal frequency for indicating clear track conditions, caution signal means actuated by said selective control means in response to another signal frequency for indicating advance track conditions requiring caution, brake control means cooperative with said caution signal means, manual switch means connected with said brake control means and operable to prevent the actuation of said brake control means in conjunction with said caution signal'means, and speed control means including a train actuated speedometer system having contacts connected between said brake control means and said manual switch means and operated by said speedometer system for functioning upon the operation of said switch means to control the actuation of said brake control means, whereby operation of the train under a caution signal is governed by said speed control means.

12. A continuous train control and signal system as set forth in claim 11 and including danger signal means and separate emergency brake controlmeans normally operative upon the absence of current of signal frequency in the rails, manually operable releasing means connected with said emergency brake control means and speed control means including a train actuated speedometer system havingcontacts connected with said releasing means and operated by said speedometer system for functioning upon the operation of said releasing means to control the actuation of said emergency brake control means, whereby operation of the train under a danger signal is governed by said speed control means.

13. A continuous train control and signal system comprising a plurality of insulated rail track sections, means for supplying current of difierent'signal frequencies to the rails of an occupied track section in accordance with track conditions in advance of said section, selective control means carried by a train in said track section responsive to the different signal frequencies of current in the rails, signal means actuated by said selective for indicating clear track conditions, caution signal means actuated by said selective control means in response to another signal frequency for indicating advance track conditions requiring caution, current actuated brake control means cooperative with said caution signal means, manual switch means connected with said brake control means and operable to prevent the actuation of said brake control means in conjunction with said caution signal means, danger signal means, and separate current-maintained emergency'brake control means normally operative upon the absence of current of either signal frequency in the rails.

JOHN C. MCDONALD.

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