US1151027A - Railway-train-controlling system. - Google Patents

Description

.J. C. McDONALD. V RAlLWAY TRAIN CONTROLLING SYSTEM.

APPLICATION FILED J UNE26, I913.

. Patented Aug. 24, 1915.

3 SHEETS-SHEET I.

1., c. McDONALD. RAILWAY TRM'N CONTROLLING SYSTEM.

APPLICATION FILED IUNE26, I913.

' Patented Aug. 24, 1915.

3 SHEETS-SHEET 2.

s. c. McD'ONAhD. RAILWAY TRAIN CONTROLLING SYSTEM.

APPLICATION HLED IJUNEZG. I913.

1,151,2Y. Patented Aug. 24,1915.

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. tate the operation of. railways; to reduce the JOHN G. lvicnoivann, or unw oan, n. a.

.RAILWAY-TRAIN-CONTROLLiNG 'srsrniu.

Specification of Letters Patent. Patented A11 24, 1915.

' Application filed June 26, 1913.. Serial No. 775,879.

To all who-m it may concern Be it known that 1, JOHN C. MCDONALD, a citizen of the United States, and a resident of New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Railway-Train-Controlling Systems, of which the following is a specification. I My invention relates to improvements in railway train'controlling' systems, and par ticularly combined automatic signal, trainstop, and speed-control systems, and comprises a system equally applicable to roads operated by electric energy derived from a stationary generating plant, and'to roads employing individual power units for each train, such as steam locomotives and storage battery motor cars.

My invention comprises stationary signals and signal-circuits and controlling instruments therefor, combined :with traincontrol circuits, which are carried by the trains and are arranged to be made effective for the control of the trains by contact of contact shoes or the like carried by the trains with sectional conductors located along thetrack; and my invention further comprises means whereby the speed of trains is controlled; all as hereinafter described and pointed out in the appended claims.

' The objects of my invention are to facililiability to collisions; to provide effective means for positively stopping trains; to prevent entry thereof into blocks which are already occupied, or the signals of which are. at danger; to provide simple means for the automatic control of train speed; to provide a system which may be applied readily and at relatively small expense to existing roads employing separate power units, such as steam locomotives, for the individual trains; andgenerally to make the circuits and appa- 1 ratus of the systems simple and reliable and to cause such circuits andapparatus to afford ample protection to trains.

I will now proceed to describe my invention with reference to the accompanying drawings, and will then point out the novel features in claims.

In the drawings, Figure 1 is a diagrammatic view showing circuits and instruments for one track of a double track railway, the

direction of normal progress along such track being indicated by an arrow. Fig. 2

is a diagram illustrating an alternative 'arran'gement of circuits, this figure illustrating the fact that the controlling circuits of the secondary relay need not pass through contactsof a secondary relay of a block in advance as well as through contact points of a primar relay of a block in advance. Fig;

' 31s anot er diagrammatic view illustrating the fact that the secondary relays may operate upon normally closed circuit instead of upon normally open circuit. Fig. 4 is a view illustrating diagrammatically the control of a locomotive throttle valve and brake valve by the holding coil H of the train circuit.

In the embodiments of my invention herein illustrated and described, one,'and preferably both, of the two parallel rails of each track, are insulated from the ground and divided into block sections, such sections being insulated from each other; and track circuits are provided which include the insulated rail sections, by which track circuits suitable relays, circuit breakers, or switches, contro1 ling signals and controlling the automatic stop circuits, are operated as hereinafter described. But it will be understood that. the said relays or automatic switches may be operated by any of the well known equivalents for track circuits, so that track circuits are not fundamentally required in my system; though they are convenient.

Referring first to Fig. 1; T T etc., designate block sections of the track rails, insu- 3 lated from the ground and from each other; A, A etc., represent suitable track circuits,

batteries or. electric generators connected to the track rails T T etc., respectively; so that the said batteries and their connections, with therail sections T T etc., form track circuits adapted to be short circuited by the wheels of a car or train passing over the track. For each block a suitable main re'lay or switch MB. or MR etc., is provided, connected to the corresponding insulated rail section T or T or T etc., as the case may be, by suitable conductors 1 and 2, the arrangement being such that the magnet of each main relay is normally energized; its operating track circuit, however, being arranged to be short circuited, and the magnet being therefore. arranged to be deenergized, by the wheels and axles of a car' or train passing on to the corresponding block. Each main relay is provided with front conlit) a signal battery or generator 9, of which there is one for each block. In Fig.1 I have indicated that each of these signal batteries 9isf grounde'd on one side and have indi-,

cated each signal conductor 8 as extending from the corresponding rear contact of its main relay MR or MR etc., as thecase may be, through its corresponding danger signal D to a caution signal C at the block next in rear and thence to ground; there being, therefore, Ithree signals at the entrance of each block, namely, a safety signals, a caution signal C, and a danger signal D; but

I obviously the caution signals C may be omitted,.if desired. 4

It will be apparent that these signals will be operated as follows: When any particu'lar'block is clear, that is to say, when there is no car on that, block, the magnet of the corresponding main relay MR or MR, etc.,

y will be energized, and the safety signal S of that block will be displayed ;"-but when thereisa car on any block, the magnet-of the; main relay MR MR etc., as the case may be,'will be deenergized, through the short circuiting'of the track circuit of that block by the wheels and axles of that car,

- and the danger signal D of that block, and

. run into a danger block or past a danger the caution signal C of the block next in rear, will be displayed, and the safety signal played;

' S {of the block sooccupied will not be dis- I willnow proceed to describe the means, entirely independent of' thesignal circuits just above described, for the positive, control and stopping of the trains which may signal. For. this purpose, I provide, at a I suitable -point in each block, a contact rail designated fin the drawings by the letter L or L or L etc., as the case maybe. These'contact rail sections L L L etc., should be arranged parallel to the track rails and a short-distance therefrom, and may be ,on either side of the track. vThey should be so placed that a suitable contact shoe or gotherconvenient contact device M carried 'by the'locomotive or lea ding car of the train,

will contact with such contact rail sections as such locomotive or car passes such contact' rail sections. The manner of support of such contact shoes M on the locomotive or cars is well understood, andis not vnecess'aryto be described here. The contact rail sections L L etc., should have at least a length such that a car or train, when pass- 1 ing at the maximum speed over the track,

will remain in contact with such contact rail I section for a period long enough for the operation, of a train relay or switch also car'- ried by such locomotive or car. -.In most cases a length of ninety toone hundred feet for these contact rail sections L ,L etc., will be suflicient though a greater length is not objectionable, and in fact, the longer these rail sections L L etc., are, the better; for the longer these sections are, the longer is the period within which the car or train stop device. 7 i

Each locomotive or'motor car is provided with a train relay or switch TR and with a is under'absolute control of the automatic train battery or generator TBQ. Norl'nally'- this train relay is energized by current from,

battery TB through conductor "10 leading toan axle bearing and therefore the axle magnet. of the train relay and thence through conductor 11,- shoe M and thence back to battery TB. When shoe, M makes contact with one of the contact rail sections.

' and its wheels) oftlie car, and thence to the L L ,.L etc.,, the relay will be shunted closed so long as said coil is energized; while when said coil is deenergized, the throttle valve is closed and the'air brake valve opened, so shutting off power-and applying the brakes.

In order that the relay TR may be deenergized, to effect the deenergization of the holding coil H, and therefore to bring the train to rest, it is necessary. that'when the contact shoe M of the trainis in contact with one of thecontact'rail sections L L etc., that contact rail section shall be electrically connected to one-of the track rails of the corresponding'block and so through the wheels and axles to the conductor 10. To this endI provide at .each blocka secondary relay or switch SR SR SR etc., each such secondary relay having .a rear contact-17 which, ,when completed, connects conductors 18 and 19leading from one of the track rails and from the corresponding contact rail section L L L respectively. Each such secondary relay has also a con tact 20 controlling 'the circuit of the corresponding secondary relay of the block next in rear. To this end a ground connection G or G or' G etc., is provided at each block, a conductor 21 leading from such ground connection to rear contact 20 of the corresponding secondary relay of that block,

' through conductor 22 to that track railof the block to whichconductorlS is connected, thence through conductor 18 to contact 17 of that relay, thence through conductor 19 to contact rail section L", L etc., of that block; and from such contact rail section a conductor leads through a battery 24 to other rear contacts 25 of the corresponding secondary relay .of that block, and thence a conductor 26 leads to front contacts 27 of the main relay MR or MR or MR as the case may be, of that block; from which front contacts a further conductor 28 leads to a front contact 29 of a delay action relay Dll, DIP, DR" etc., of the block next in rear. whence a conductor 30 leads to the magnet of the secondary relay SR or SR or SR, as the case may be, of such block next in rear, and thence to a rear contact 31 of the main relay MR, orMR or MR etc., of such rear block, and thence to a further ground G", or G, etc., of that block next in rear. It will be seen that the circuits and connections are such that when the magnet of any main relay MR or MR etc., is energized, the magnet of the corresponding secondary relay must be delinergized, and the rear contacts of'that secondary relay closed; but when the magnet of. any main relay MR or MR etc., is dcenergizcd, the magnet of the corresponding secondary relay SR SR etc. may be energized, provided the contact of the correspmiding dclay action relay DR, Dll etc., be closed,

and provided the magnets of the main re-' layMlt, or MB, or MR, as the case may be, of the block next beyond, be energized, and provided the magnet of the secondary relay'SR, or 811*, or SR, as the case may be. of the block next beyond, be delinergized.

The delay action relays, or time relays, as they are sometimes termed, DR, D1 etc., are relays which close their contacts a determined interval after their magnets are energized. They may be of any suitable construction. As a diagranimatic representation of such relays, I have indicated relays the armatures of which are retarded by dash pots. Each delay action relay is in a local circuit controlled by a rear contact of the. corresponding main relay MR, MR

etc. I

The operation of these train control and automatic stop circuits is as follows: Suppose a train to pass from block T to block 'l. the latter block being otherwise unoccupied. and block T being unoccupied. As the train enters block T the main relay MR of that block isoperated. its front. contacts being broken and its rear contacts closed, and thereby the danger signal I) at the entrance of that block T and caution signal C at the entrance of the block T, are displayed. and the magnet of the correspondcontact 29 of relay DH is closed, so that the connection of contact rail section L to one of the track rails T is broken at contact 17 of relay SR therefore when, as the train passes on in block T its shoe M contacts with the contact rail section L the shunt circuit from the train battery TB through the shoe M, contact rail section L conductors 19 and 18, track rails/T the wheels and ,axles, and conductor 10, is not completed, and therefore the magnet of train relay TR remains energized and the holding coil H does not operate. But should relays, therefore, it is possible to limit the speed at which trains may move. lVhen the train has passed. completely into block T the magnet of the main relay MR of block T is energized, the danger signal D of that block is no longer displayed, and the safety signal S of that block is displayed, the caution signal C of that block remaining displayed since block T is now occupied. The train in block T is then protected in rear by the caution signal C of the block T and by the danger signal D of the block T Suppose, however, that when the trainso passes .into block T block T is already occupied. In such case the caution signal C at the entrance of the block T Will be displayed, and the danger signal D at the entrance of block T will be displayed. If, by the time the contact shoe M of the train in block T reaches the contact shoe L block T is still occupied. the magnet of' secondary relay SR will still be denergized 7 By proper regulation of the speed of'operation of the delay action and the shoe M of the train in block T mal ing contact with contact rail section L will complete the circuit which shunts out TB, be broken. the relay will also be deenergized and the train brought to rest. It will be apparent that if for any reason the shoe M be torn from the train. the relay TR will be deenergized and therefore the train will be brought to rest. One purpose of passing the controlling! conductors 2 3, and 19, and thereby to break the: controlling circuit of relay SR of the block next in rear. Therefore, when atrain next entersjblock T the magnet of relay SR cannot be energized and therefore the 1 5: train which has so entered block T 2 Will be brought to rest, indication being thus given of trouble-Fin block T.

v InFig. 2 I-illustrate a system which is :simila'r'to' that of Fig. 1, except that the cir- 20. cuits are-somewhat simplified by the omis- S 0n, of certain of the features of the circuits ..of Fig. InFig. 2, the contacts of the secondary relay, SR SR etc., are omitted,

also the contacts of those relays, and the 5f'contro-lling circuit of the secondary relay of each block-passes from ground G, G etc.,

'of the corresponding block, through the rear v contact 31 of the corresponding main relay MR R etc., and'through the magnet of 3 the said secondary relay and thence through the Contact 29 of the corresponding delay,

- shown each 'such contact conductor located a action= relay DR, -DR etc., and thence t'l'iroug h, conductor 28 to contact 27 of the 1,..- .;.m=an relay MR MR etc., of the block nest ,inadvance; and thence through battery 24 to ground. 1 Passing the controlling cir- (suit of each .secondaryrelay throughcon tacts of-the secondary relay of the block in advance'as well asthrough contacts of the 0 main 1"e1a 0 such .block in advance has certainadvantages, inthat a. certain degree of additional protection may be secured thereby"; b'utin inanycases'such additional pro tecti-oir'is unnecessary, andthe's nlplifiedcircuit shown in Fig. may be used.f

Passingthecontrolling circuit of each sec ondary relay through the contact railsection I). I etcr,.ottheblock'nextflin advance as; r 4 7 isin'dicat'edlifrFig, L also'h'as certain adfvantagcs, as. explained above,f.but in some cases. this -i'nay notbe deemed necessary, and

thereforein 2 the controlling circuit of {eachsecondary relay is not passed through the contact rail section L,-L etc., of the block'nextfin advance.

. In the circuitsshown' 'n Fig.2, instead of 'passing.tlie liattery-conductor 10 of the rails g1TR' through one of the axle bearings. as in' Fig. 1, I have: connected. that conductor 10 itti one of the-axle bearings, and therefore to t orresponding -axle and wheels, by a con- 12. The operation of the circuit of ntrolliiig circuit of relay TR is the the same as 'in Fig. 1, except that should the --cond'iictor-12 be brokendeenergization of re next block displayed, so that the operation lay TR does not t'ollow. However, in most cases this conductor 12 can be led and protected in such manner that there is filo may contact with one of the contact conductors L L etc. when the corresponding switch 32 is open; These switches 32 may be employed with advantage at crossings, draw bridges, switches, etc., to prevent passage of trains through a block when the crossing gates are raised, or the draw bridge open, or a switclropen. In Fig. 2 I further indicate that the train relay TR may control a cab signal, thereindicated as a semaphore arm 33, which arm is connected by a rod 34 to. the plunger 35 of a coil 36 connected in 7 parallel withholding coil H; a spring 37 tending to press the semaphore arm to danger position against'the pull of coil 36.

'The contact rail sections or conductors L L etc.,' may be of any suitable length and may be placed wherever thought best in their respective blocks. In Fig. 1 I have short distance beyond the entrance to its corresponding block (such distance being, preferably, a distance such that in most cases the trains maybe brought'to restiby prompt application of brakes upon first signa-lof that block displayed, and will bring his train to rest before he reaches the contact rail sect on L, Ifi'etc, of that block, if he finds the danger signal of the of the'automatic stopping device described 'is required only in the eventthat the engineer permits his train to proceed far enough into a block to make contact with the contactconductor L. L ctc. of that block notwithstanding that the danger signal of the block next ahead is (lg-played. iy locating-these contact conductors L, If, etc.. near the entrance of the block next ahead but sufii: ciently distant therefrom to insure a train being brought to rest without passing a. danger signal, trains are permitted to proceed with caution pasta caution signal until arrested at one otthe contact conductors 130 block. and without diminution ofthe factor L L etc., provided the block ahead be 'SiilllOCCilPlQtl, and thereby the train capacity of the system is considerably increased as compared with the arrangement wherein the contact conductors are eachlocated just beyond the entrance of the corresponding of safety.

In general, when the contact conductors L L?, etc., are located near the entrance of the block in advance, as indicated in Fig. 52, the danger signal of the block in advance will be visible, if displayed, before reaching such contact conductor; but when this is not the case,'additional caution signals C may ibe provided about opposite the eta-responds 'ing contact rail sections L, If. etc., and in the same circuits with the danger signals next ahead. 4 v

,The secondary,relays' do not necessarily operate on normally'open circuit. In Fig.

311 illustrate circuits in which the secondary relays. there designated by characters Sh SR etc operate upon normally closed cir cuit. A simplified arrangement of circuits,

in general similar to those of Fig. 2, is illustralte'd. Each secondary relay has two magnet coils, one in a circuit passing from ground G 1?, etc., of the block in advance through a rear contact 38 of the main relay I etc., of such block in advance and thr'ough conductor 28 tov the coil 39 of such secondary relay, and thence to ground; the other coil, 40, of such secondary relay being in a circuit passing from ground through spring contact points 41 and 42 of the'correspondingdelay action relay DR, DB etc., and through battery 2i and said coil 40 to ground. In this arrangement, each main relay MR MR etc., controls the circuit of its corresponding secondary relay by controlling the corresponding delay act-ion relay DR. DB etc. and these 7 7 3 delay action relays are controlled by front contacts 43 of the corresponding primary ormain i'i'elays MR MR etc. The operationlof tie circuits shown in Fig. 3 is ineffect the sameas that of the circuits shown 4 in Fig. '2. :The delay action relays of Fig.

- block, a. train contact 3'are relays which open their cont-acts a pre-" determined interval after the magnets of said relays are deenergized.

In this specification I use the term train 'to designate anything from a single car or locomotiveto'a train composed of a number of cars; and I use the term relay as inclusive of any mechanically actuated or electrizally actuated circuit breaker on circuit closer.

What I cla m 1s:

1. A railway train controlling system' comprising in combination a track divided into blocks, a contact conductor for each device adapted to make contact with such contact conductors, a. train train-controll'ing means, a source circuit comprising electrically tial circuit controlled by it when the corresponding primary relay is in a conditioncorresponding to an occupied condition of its correspmnling block. and when the prhnary relay-of the said advance. block is in a con dition corresponding to clear condition of its corresponding block.

2. A railway train controlling system. comprising in combination atrack divided. into blocks, .a contact conductor for each block, a. train contact device adapted to make contact with such contact conductors, a train circuit comprising electrically controlled train-controlling means, a source of electric energy and a part electrically cow nectedwith a track rail, a primary relay for each block. controlled bytrains passing along said track, and means normally closing connection between the contact conduc-. tor of each block and the track rail of the corresponding block, such means arranged to open such connection between said contact conductor and track rail when a train enters said block, provided the block ahead is clear. i

3. A railway train controlling system comprising in combination a track divided into blocks. a contact conductor for each block, a train contact device adapted to make contact with such contact conductors, a train circuit comprising electrically controlled train-controlling means, a source of electric energy and a part electrically conv nected with a track rail, a primary relay for each block, controlled by trains passing along said track. means normally closing connection between the contact conductor of each block and the track rail of the. corresponding block. such means arranged to open such connection between said contact conductor and track rail after a train enters said'block. provided the block ahead is clear, and means preventingopening of such connection for a predetermined interval following the entry of such train into sucliblocki l. A railway train cdntrolling system comprising in combination a track divided into blocks, 'a contact conductor for each block, a train contact device adapted to'make contact with such contact- .conductors, a train saidtrack, normally closing'connection between the contact conductor ofeach block and the track rail of the corresponding block, such means arranged toopen such connection between said contact conductor and track rail after-a train enters said block,

provided the block ahead is clear, and a delay-action relay arranged toprevent the opening of such connection for a predetermined interval following the entry of such 1 train into such block, v

5. A railway train controlling system comprising in combination a track divided intoblocks, a contact conductor for each block, a train contact device adapted to make contact with such contact conductors, a train circuit comprising electrically controlled train-controlling means, a source of electric energy and shunt connections to said train contact device and to a track rail, a primary relay for each block, means for operating the same operated by trains pass ing along said track, a secondary relay for each block, a' circuit controlled by saidsecondary relay and which when completed closes connection between the contact conductor for that block and the track rail of that block with which the said train circuit is connected, an operating circuit for each such secondary relay controlled by the corresponding primary relay and by the primary relay of a block in advance, and arranged to cause such secondary relay to break the said circuit controlled by it when the corresponding primary relay is in a condition corresponding to an occupied condition of its corresponding block, and when the primary relay of the said advance block is in a condition corresponding to clear condition of its corresponding block, and means fol-delaying the breaking of the said connection between the contact conductor and track rail for a predeterminedinterval 01 lowing the entry of a train into the corresponding block. y

(3. Ar railway train controlling system comprising in combination a track divided into blocks, a contact conductor for each block, a train contact device adapted to make contact with such contact conductors, a train circuitcomprising electrically controlled traincontrolling means, a source of electric energy and shunt connections to said train contact device and to a track rail, a primary relay for each block, means-for operating the same operated by trains passing along said track, a secondary relay for each block, a circuit controlled 'by said secondary relay and which when completed closes connection between the contact conductor for that block *to' an occupiedcondition of its correspond- "ingfl block, and when the primary relay of passi ng along said track, a secondary relay and the track rail of that block with whr the said train. circuit is connected, an operating circuit for each such secondary relay controlled by the corresponding primary relay and by the primary relay of a block ondary relay to break the said circuit controlled by it when the corresponding primary relay is in a condition corresponding the-"said advance block is in a condition corresponding to clear condltlon-of its corre- 1 sponding block, and a delay action relay for each block controlled by the primary relay v1n advance, and arranged to cause such secof that block and controlling the operating circuit of the secondary relay of such block and. arranged to prevent operation of such secondary relay for a predetermined in terval following the entry of a train intothe corresponding block. p

7. A railway train controllingpsystem comprising'in combination a track divided into blocks, a contact conductor for each block, a train contact device adapted to make I contact with such contact conductors, train controlling means arranged to be operated by closing of contact between such train contact device and one of. said contact conductors, means for rendering the closing of such. contact ineffective in the event that at the time of closing such contact the block in advance is clear, and means for renderingeffective the'closing of such contact between the train contact device and contact conductor, notwithstanding that'such block ahead. be clear, if such contact be iclosed within a predetermined interval following the entry of the train into the corresponding block.'

8. A railway t 'ain controlling system comprising in combination a track divided into blocks, a contact conductor for each block adapted to make contact with contact devices carried by trains passing over said track, a primary relay for each block, means for operating the same operated by. trains passing along said track, a secondary relay adapted to open and close connection between the contact conductor of each block and one of the tack rails of that block, such secondary relay being controlled by the primary relay of its own block, and also by the primaryrelay of a block-in advance, and means for delaying action of said secondary relay for a predetermined time following the entry of the train into the cor- "vices carried by trains passing over said track, a primary relay for each block, means for operating the same operated by trains adapted to open and close connection between the contact conductor of-each block and one of the track rails of that block, such entry of the train into the corresponding block, and blocksignaling means for each primary relay block controlled by the [10. 'A railway train controlling system comprising in combination -a track divided into blocks, acontact conductor for each block adapted to'm'ake contact with, contact devices of trains passing over that track, a prim'aryrelay for each block, means for opemting the same operated by trains passing along said track, a secondary'relay for each block normally closing connection between the contact conductor of that block and one of the trackrails, circuits controlling said secondary relays and controlled by the pri- -mary relays, whereby each secondary relay is controlled both by the corresponding primary relay and by-ltjhe primary relay of a block in aclraiice,'and*is adapted to break the connection- 'bet'wee the contact conductor and track rail controlledbyit after the corresponding primary relay has operated consequent upon the entry of a train into the corresponding block, and provided the block ahead be clear, and'means for delaying such action of each secondary relay for a. predetermined time following such operation ofthe corresponding primary relay. I

. 11. A railway train controlling system comprising in combination a track divided into blocks, a contact conductor for each. block adapted to make contact with contact devices of trains passing over that track, a primary relay for each block, means for operating the same operated by trains passing along said-track, a secondary relay for. each block norm-ally closing connections between the contact conductor of that'block and one of the "track rails, circuits controlling saidsecondary relays and controlled by the primary relays, whereby each secondary relay is controlled bothby the correspondingprimary-relay and by the primary relay of a block in advance, and is adapted to break th'econnection between the contact conductor and track rail controlled by it after the corresponding primary relay has operated consequent upon the entry of a train into the corresponding block, and provided the block ahead be clear, and a delay action relay for each block, controlled bytheprimary relay of that block, and controlling the controlling circuit of the secondary relay of that block,

and arranged to delay, for a predetermined lnterval, actlon of the'coi'rresponding secondary relay following action of the cone sponding primary relay consequent upon entry of a train into the corresponding block, A railway train controlling system comprising in combination a track divided circuited by a train entering that block, a

secondary relay for each block normally closing a connection between the contact conductor of that blockandone of the track rails, a normally open circuit for controlling each. secondary relay, such circuit controlled by a rear contact of the corresponding primary relay and by a front contact of the primary relay of a block irradvance, and a delay action relay likewise controlling such secondary relay circuit and itself controlled by a rear contact of the corresponding primary relay, such delay action relay arranged to prevent completion of the controlling circuit of the corresponding secondary relay for a predetermined interval following retraction of the armature of the corresponding primary relay.

13. A railway train controlling system comprising in combination a track divided into blocks, a contact conductor for each block adapted to make contact with contact devices of trains passing over said track, a

primary relay for each block, a normally .relay of a block in advance, a delay action relay likewise controlling such secondary relay circuit and itself controlled by a rear contact of the corresponding primary relay, such delay action relay arranged to prevent completion of the controlling circuit of the corresponding secondary relav for a predetermined interval following retraction .of the armature of the corresponding primary relay, and block signals likewise controlledby the said primary relays.

14. A railway train controlling system comprising in combination a track divided into blocks, a contact conductor for each block adapted to contactwith' train contact devices of trains passing over said track,

train-controlling means arranged to be actuated by closing of contact of such train contact devices With such contact conductors,

means for rendering the closing of such conblock located near the entrance'of the next succeeding block, a train contact device.

adapted to make contact with such contact conductors, train controlling means arranged to be operated by closing of contact between such train contact devices and one of said contact conductors, a primaryrelay for each blockpa track circuitfor] each primary relay controlling the same, a dan-' gei' signal'controlled by each primary relay;

a caution signal controlled" by each primary relay and located in proximity to the contact conductor of the block. next in rear, and a secondary relay for each block, controlled by the pri maryrelay of that block and also by the primary relay of the block next in advance; and arranged to be operated by its primary relay, to -make-inefl'ective contact between a train contact device and the' contact conductor of the corresponding block, upon the operation of the corresponding primary rela'y consequent upon the entry of a train into that and provided block next in advancej be clearij r 16 railway gr-t' iitl ln controlling system comprislng it-combination a track divided into blocks, a contact conductor for each block, a train contact device adaptedfto make contact with such contact conductoi'sf train controlling means arranged toqbe operated by closing of contact-between such train contact deviceand one of said contact conductors, a primary relay for each block, a track circuit for each primary relay con trolling the same, danger and safety sig r rals for each block controlled by the corresponding primary relay, a secondary relay each block controlled by the primary relay of that block and by the secondary relay of a block in advance, said secondary relays each provided with means for rendering inefiective the closing of contact between a train contact device and the corresponding ,contact conductorof that block, upon the operation of the corresponding primary relay'consequent upon the entry of such train v into that block, and provided the block next in advance be clear.

v Iiftestimfony whereof I have signed this,

specification in the presence of two subscribing witnesses. 7

JOHN C? MCDONALD.

Witnesses:

H'. M LiA RBLE, F. S; Ross.

comma! tlihpatent may be obtained tonfive cents each, by addressing the commissioner 01 Patents,

wishington, i5. 0."

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