US1419869A - Railway traffic-controlling apparatus - Google Patents

Description

L. V. LEWIS.

RAILWAY TRAFFIC CONTROLLING APPARATUS.

APPLICATION FILED SEPT-1|.1919.

1 9 69 v Patent-ed June 113, 1922.

3 SHEETSSHEET I.

AMPLIFIERJ' f/ 0 a L M 115105717 95 B APPLIES B34512? 104 WHEN DE-EVEZZGIZED DEVICE DRIVEN BY (AR T WIEZJL.

L. V. LEWIS.

RAILWAY TRAFFICCONTROLLING APPARATUS.

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APPLICATION FILED SEPT-11,1919. 1,419,869,

L. v. LEwis.

RAILWAY TRAFFIC CONTROLLING APPARATUS.

APPLLCATJON FlLED SEPT. 1!. i919.

1,419,869, I Patented June 13, 1922.

3 SHEETSSHEET 3.

INVENTOR.

1M ATmieA/EK Nil? ATENT FFH.

LLOYD V. LEWIS, F WINSBUB/G, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORA TION OF PENNSYLVANIA.

RAILWAY TRAFFIC-CONTROLLING APPTUS.

misses.

Specification of Letters Patent. Patent d J 13 1922 Application filed September 11, 1919. serial No. 323,168.

T 0 (1H whom it may concern:

Be it known that l, LLOYD V. Lnwrs a. citizen of the United States. residing at Vilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Railway T radio-Controlling Apparatus, of which the following is a specification.

My invention relates to railway traflic controlling apparatus, and particularly to apparatus for controlling the speed of railway cars or trains.

A railway signaling system usually includes roadside signals which give restrictive and non-restrictive indications. When an automatic. speed controlling system is provided in connection with a signaling syst m of this kind, the apparatus is usually arranged to permit a train to travel at different speeds depending on the indications given by the signals. A systemof automatic control arranged to operate in the manner set forthhas one undesirable feature, however, in that it may permit the engineer to disregard his duty and rely on the automatic apparatus to control the train in the event of dangerous traflic conditions 1 in advance.

This is undesirable, because even if we assume that the automatic apparatus is capable of handling the train equally as well as the engineer. can handle it, it is still a mechanical device and no matter how perfect it may be, it may 'fail. On the other hand, we know the engineer is certain to fail, at times. The reliability of the engineer depends largely upon his sense of responsibility and physiological fitness, while the automatic device is independent of such variable conditions. To get the best results from the engineer we must depend upon him and must hold him responsible for the proper observance of signals.

With this accomplished and the automatic control added, we have the latter in reserve if the engineer fails, and the chances of trouble arereduced to the very remote contingency of the simultaneous failure of both,

normally causing the train to come to a stop or to a low speed upon passing a signal which gives a restrictive indication, together with means under the control of the engineer for suppressing such stopping means and permitting the train to proceed in accordance with the indication given by the signal provided that the engineer acknowledges the signal by a suitable manual action while passing the same.

I will describe two forms of apparatus embodying my invention, and will then, point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a view showing one form of train carried electrical apparatus embodying my invention. Fig. 2 is a view showing one form of train carried fluid pressure apparatus embodying my invention. Fig. 3 is a diagrammatic view showing one form of trac kway apparatus which may be employed in connection with the train carried apparatus shown in either of the preceding views.

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

Referring first to Fig. 3, the reference characters R and R? designate the track rails of a railway, which rails are divided by insulated joints 2 to form blocks A--B, B-C, etc. Traflic along the railway is normally in the direction indicated by the arrow.

Located adjacent the entrance of each block is a roadside signal designated by the reference character S with an exponent corresponding to the location. Each signal, as here shown, is of the semaphore type, adapted to indicate stop, caution or proceed according as the semaphore is in the horizontal, inclined or vertical position. The control circuits for these signals form no-part of my invention and so they are omitted from the drawing, butit is understood that in accordance with usual practice each signal indicates sto when the corresponding block is occupied, caution when the corresponding block is unoccupied and the block next in advance is occupied, and proceed when the corresponding block and the block next in advance are unoccupied. For exam 1e, as shown in the drawing the block to t e right of location 0 is occupied by a vehicle V, so that signal S for this block is at stop, signal S for the block next in the rear is at caution, and signal S for the second block in the rear of the occupied block is at proceed.

Each block is provided with a track circuit comprising as usual the track rails' of the block, a source of alternating signaling current connected across the rails adjacent the exit end of the block, and a track relay having a winding connected across the rails adjacent the entrance end of the block. The source of current for each track circuit is the secondary of a transformer which is designated T with an exponent corresponding to the location, and the relay for each track circuit is designated by the reference character H with an exponent corresponding to the location.

Each trackrelay H is of a three-position type, comprising a track winding 4, a second or local winding 5, a rotor 6, and a contact finger 7 operated by the rotor. The track Windin 4 is connected directly with the track rai s, and the local winding 5 is constantly connected with a transmission line P to which alternating signaling current is supplied by a generator 8. Each of these relays, then, responds to reversals of the polarity 'of the current in the corresponding track circuit with respect to that of the transmission line P, so that the hontact-finger 7 is swung to the right when the track circuit is of one polarity (which I will call normal), and to the left when the track circuit is of the other polarity (which I will term reverse). The contact finger occupies an intermediate or vertical position when the track winding of the relay is deenergized.

The primary of each track transformer T is connected with the transmission line P through the medium of a pole-changer N which is operated by the adjacent signal in such manner that when a signal indicates stop, current of reverse polarity is supplied to the track circuit for the block in the rear, but that when the signal'indicates caution or proceed, current of normal Ipolarity is supplied to the track circuit. t follows, then, that the track relay for each block is energized in the reverse direction when the block next in advance is occupied, and in the normal direction when the said block next in advance is unoccupied.

Means are provided for each block for supplying to the rails thereof a second alternating current, which I willterm'the line circuit current, and which current flows in the same direction in both rails of-the block. This current is supplied by a transformer located at the entrance end of the block and designated by the reference character U with an exponent corresponding to the location. The prime of each of these transformers is connecte directly with the transmission 'axle and a pair of wheels.

line P. This current is led into the track rails through connections at the middle points-of resistances which are connected across the rails and which are'designated by the reference character M with suitable exponents. Three of these resistances are provided for each block, two at the opposite ends of the block designated M and M and the third at an intermediate point in the block designated M Resistance M for 'each block is located a distance in the rear of the exit. end of the block substantially equal to the maximum braking distance of a train traveling at an intermediate speed, which speed, as hereinafter chosen arbitrarily, is 35 miles per hour. Each block is,

therefore, divided by the resistance M into From the foregoing it will be seen that means are provided for each block for supplying two superimposed alternating signaling currents to the rails thereof, one of which currents flows in opposite directions in the two rails, while the other current flows in the same. direction along the rails. An inductive resistance 3 is included in the secondary circuit of each transformer T, and a non-inductive resistance 24 is included in the secondary circuit of each transformer U, so that the currents from the two transformers are displaced substantially 90 in phase in the track rails.

Referring now to Fig.1, the reference character V designates a railway vehicle (a car or train), which is represented by an Mounted on this vehicle in advance of the forward axle are two pairs of laminated soft iron cores 34 and 34", the two cores of each pair being located over the two track rails R and R respectively. Each core is U-shaped with its legs .pointing downwardly, and each core is disposed transversely wit respect to the rail. It is apparent, therefore. that when alternating current flows in either rail, part of the magnetic lines of force surrounding such rail will pass through the cores which are directly over the rail, and so will induce an alternating potential in any coils which the cores may carry.

" The cores 34, 34 are provided with coils 35 and 36, respectively; and the cores 34, 34*, are similarly provided with coils 35 and 36 The coils 35 and 36 are included in a receiving circuit, a, the coils being so connected in this circuit that the potentials created in these coils by alternating current flowing in opposite directions in the two rails are additive, while the potentials created in these coils by currents flowing in the same direction in the two rails oppose each other and so cause no current in circuit (I. Track circuit current from transformers T, therefore, induces current in circuit a, but the line circuit current supplied by transformers U produces no current in this circuit.

Coils 35 and 36 are included in series in a receiving circuit 6, the coils being, connected in this circuit in such manner that the potentials created in these coils by currents The currents thus induced in the receiving circuits a and b are utilized to control the supply of currents to the two stator windings 37 and 38 of an induction motor relay F, suit-able amplifying apparatus preferably being interposed between the receiving circuits and the relay windings, as indicated in the drawing. Relay F also comprises a rotor member 39 which controls two contact fingers 40 and 40*, these fingers being normally biased to occupy vertical positions when the relay is not energized. Inasmuch as the two currents in the track rails are displaced in phase, it follows that the currents in relay windings 37 and 38 will similarly be displaced in phase, so that torque will be exerted on the rotor member 39 in one direction or theother. depending on the relative instantaneous polarities of the currents in the track rails. When the polarity of the track circuit current is normal, re'lay F isenergized in normal direction wherein contact fingers 40 and 4:0.are swung to theright; and when the polarity of the track circuit current is reverse, relay F is energized in reverse direction wherein the contact fingers are swung to the left.

Relay F controls two relays 85 and 85 in such manner that both relays are enerized when relay F is energized in normal direction, and that relay 85 becomes deenergized but relay 85 remains energized when relay F is reversed. The two relays 85 and 85 are controlled directly by the contact fingers 40 and 40 of relay F, the circuits being obvious from the drawing.

The relays 85 and 85, together with a circuit controlling device Q, serve to govern open at the same contact of relay 85".

in such manner that it occupies the position in which it is shown when the vehicle is at rest, but that it is swung to the left around its pivotal point 90 while the train is in motion. This arm 90 coacts with contact segments 91, 92 and 93 in such manner that when the'speed of the train exceeds 10 miles per hour. contact 90-91 becomes opened; when the speed of the train exceeds 35 miles per hour, contact 90 92 becomes opened; and when the speed of the train exceeds 65 miles per hour, contact 90-93 is opened.

The reference character 88 designates a push button under the control of the engineier for suppressing an automatic application of the brakes, as hereinafter explained.

Assuming that the vehicle V enters block A--B in Fig. 3, it is apparent that relay F will be energized in normal direction because track circuit current of normal polarity is supplied to the rails of this block. Relays 85 and 85 are, therefore, energized, and the following circuit for the brake application magnet- 89 is elosecl-f!'om terminal B of a suitable source of current, through contact 96 of relay 85, wires 97 and 98, contact 93-90 of circuit controller Q, and brake magnet 89 to terminal 0 of the same source of current. quently. proceed through block AB at a speed not exceeding 65 miles per hour without incurring an automatic application of the brakes.

When the vehicle V enters block 13-4. relay F will become energized in reverse direction because track circuitcurrent of reverse polarit is supplied to the rails of this block, the b ock next in advance being occupied by a vehicle V. Relay 8?) will then become tie-energized, but relay 85 will re-.

main energized. First, assuming that the engineer takes no action while passing point B, it is obvious that the circuit just traced for valve magnet 89 Will be opened at contact 96 of relay 85. The circuit including contact 90-92 of circuit controller Q is If the speed of the train exceeds 15 miles per hour, the circuit including contact 90-91 of circuit controller Q will also be open, but if the speed of the train is 15 milesper hour or less, valve magnet 89 will be energized by virtue of the following circuit: from battery terminal B, through front point of contact 101 of relay 85 wires 102 and 103, back point of contact 104 of relay 87, wire 105. contact 9190, and valve magnet 89 to The train may, conse-' I 1,41 asee battery terminal 0. It follows, then, that if the speed of the train is more than 15 miles per hour, an automatic application of the brakes will occur and the train will be brought to a stop.

1 will now assume that the engineer closes push button 88 just before the vehicle passes point B. Then immediately upon the opening of relay 85, a stick relay 86 will become energized through the following circuit: from. battery terminal B, through contact 106 controlled by valve magnet 89, wire 107, push button 88, wire 108, front point of contact 109 of relay 85, wire 110, winding of relay 86, wire 111 and back contact 112 of relay 85 to battery terminal 0. As soon as relay 86 closes, a stick or holding circuit for this relay will be closed, which circuit passes from battery terminal B, through front point of contact 101 of relay 85, wires 102, 113 and 114, contact 115 of relay 86, wire 116, winding of relay 86, and back con tact 112 of relay 85 to battery terminal 0. With relay 86 closed and relay 85 closed, valve magnet 89 will be energized through the following circuit, provided that t e speed of the train does not exceed 35 miles per hour: from battery terminal B, through front point of contact 101 of relay 85, wires 102, 113 and 117, front point of contact 118 of relay 86, wire 119, contact 92-90, and valve magnet 89 to battery terminal 0. It follows, then, that if the engineer takes suitable action upon passing the caution signal at point B, the train may proceed into block B-C at a speed of 35 miles per hour or less without incurring an automatic application of the brakes.

1 will now assume that relay 86 is closed, that the vehicle passes resistance M in block B C at a speed less than 35 miles per hour, and that the engineer takes no action while passing this point. Relay F becomes deenergized at this point, because the supply of line circuit current is discontinued owing to the fact that track relay H is deenergized. Relay 85 then opens, thereby opening the stick or holding circuit for relay 86. All of the circuits for valve magnet 89 are then open, so that an automatic application of the brakes occurs and the vehicle is brought to a stop. This is true regardless of the speed at which the vehicle passes resistance M If, however, the engineer closes push button 88 while passing this point, a second stick relay 87 becomes energized by virtue of a circuit which passes from battery terminal B, through contact 106 on magnet 89, wire 107 push button 88, wire 108, back point of contact 109 of relay 8!), wire 120, winding of relay 87 and wire 121 to battery terminal 0. As soon as this relay closes, a stick or holding circuit for the relayis closed, which circuit passes from battery terminal B, through the back point of contact 101 of relay 85, wires 122 and 123, contact 124 of relay 87, wire 125, winding of relay 87, and wire 121 to battery terminal 0. Relay 87, therefore, remains closed as long as relay 85 remains open. If the speed of the train is then 10 miles per hour or less. the brake magnet 89 is energized by virtue of a circuit which passes from battery terminal B, through back point of contact 101 of relay 85*, wires 122 and 126, front point of contact 104 of relay 87, wire 105. contact 91 90, and valve magnet 89 to battery terminal 0. The vehicle can, therefore, proceed through the remainder of block li -C at 15 miles per hour or less without incurring an automatic application of the brakes, and it may, of course, enter the occupied block to the right of point C under the same restriction.

One important feature of the structure shown in Fig. 1 is the control of the pick-up circuits for relays 86 and 87 by brake magnet contact 107, the purpose of which is to prevent the suppression of a brake application after the brakes have started to apply.

In order to provide for the release of the brakes after an automatic application, 1 provide-a second push button 94, so located on the vehicle that it is accessible only when the vehicle is at a standstill, for closing the pick-up circuit of relay 87. The circuit of push button 94 is from battery terminal B, through push button 94, wires 95 and 108, back contact 109, wire 120, relay 87 wire 121 to battery terminal 0.

Referring now to Fig. 2, I will assume that the relay F shown herein is controlled in the same manner as the corresponding relay in Fig. 1. This relay comprises only one contact 40, whereby the relay controls two magnets J and J which 1 will term the high speed magnet and the medium speed magnet, respectively. As will be apparent from the drawing, the former magnet or the latter is energized according as relay 1F is energized in normal or reverse direction. The two magnets J H and J control two valve devices 41 and 41, respectively, which devices in turn control the brake apparatus as will hereinafter appear.

The immediate control of the brakes of vehicle V is effected by a brake application valve K, the control being such that the brakes are applied when the sliding member 42 of this valve moves to the left from the position shown in the drawing. The brake K is also controlled in part by a suppressed application valve X, as hereinafter set forth.

The chamber to the right of the pistons in each of the valves K, L, L, and X, are constantly supplied with air pressure by means of a pipe 46 leading .from the main reservoir of the air brake system.

The control of the valves 43 by the crosshead 45 is as follows: All of these valves are closed when the speed of the train is below 10 miles per hour. When the train exceeds this speed, however, the low speed valve 43 is opened by the crosshead 45. When the speed of the train exceeds 35 miles per hour, the medium speed valve 43 is also opened, and when the speed of the train exceeds 65 miles per hour the high speed valve 43 is opened. The valve 44 comprises a plunger which controls a plurality of ports 78 in such manner that the number of ports which are opened or uncovered by the right-hand end of the plunger varies in proportion to the actual speed of the train. The valve 44 controls a plurality of ports 72 in similar manner.

I will now assume that the vehicle V shown in Fig. 1 is equipped with the apparatus shown in Fig. 2, and'that this vehicle has entered block A-B of Fig. 3, so that relay F on the vehicle is energized in normal direction; that is, contact finger 40 is swung to the right. The high speed magnet J is then energized, the medium speed magnet J is de-energized, and ,the remaining parts of the apparatus shown in Fig. 2 are in the positions in which they are shown in this view, with the exception that the crosshead 45 will be shifted to some point "to the left, depending on the actual speed of the train. The sliding member of the high speed valve L is held in the right-hand position, because air is supplied to the lefthand face of piston 48 through the follow ing path: from main reservoir through pipe 46, body of the suppressed application valve X. and pipe 47 to the piston chamber of valve L. The sliding member of the medium speed valve 1) is held in the righthand position by air. which flows from the main reservoir, through pipe 46, valve 41*,

pipe 50, cavitv 51 in valve X, pipe 52, cavity 53 in valve L. and pipe 54 to the piston chamber of valve L. Assuming that the speed of the train is less than 65 miles per hour. the sliding member 42 of the brake application valve is held in its right-hand position, because the piston chamber of this valve is closed and air is admitted to this chamber through a small port 68 in the piston 48 of this valve. The suppressed application valve X is held in the position shown for a similar reason.

I will now assume that while proceeding throu h block A-B the speed of the train exceeds 65 miles per hour. Crosshead 45 to 15 miles per hour or less.

will then open valve 43, thereby opening the piston chamber of the brake application valve K to atmosphere through pipes 56, 57 and 79, and valve 43. The sliding member 42 of valve K will then move to the left, thereby causing an application of the brakes. This movement of member 42 will connect the piston chamber of valve K with atmosphere through pipes 56 and 61, cavity 62, pipe 63, release valve W and port 64. It follows, therefore, that the brakes cannot be released until the engineer presses the plunger of the release valve W, thus dis connecting the piston chamber of valve K from atmosphere. Operation of valve W will have noeflect until the speed has been reduced to less than 65 miles per hour.

I will now assume that the vehicle V passes point B, that is, caution signal S, at a speed greater than 15 miles per hour, and that the engineer takes no action at this point. Relay F will reverse, due to the reversal of polarity of the track circuit ourrent, thereby energizing the medium speed magnet J M and de-energizing the high speed magnet J". The reversal of valve 41 will connect the piston chamber of the medium speed valve L with atmosphere through pipe 54, cavity 53 of valve L, pipe 52, cavity 51 of valve X, pipe 50, and exhaust port 55. and, the speed of the train being above 15 miles per hour, the piston chamber of valve K will exhaust to atmosphere through pipes 56, 57 and 58, cavity 59 of valve L pipe 60, and the low speed valve 43. The brakes will thenbe applied and can only be released bv manual operation of valve W as before.

is release can, of course, be effected only after the speed of the train has been reduced The reason for making the device ineffective at speeds less than 15 miles per hour is that thereby brake applications which would result from short unavoidable gaps in the controlling track circuits as in passing from one block to another. are avoided. Thus ifvalve L has a time element of one second the train will beable to bridge a gap of 22 feet in the track circuit, at speeds of 15 miles per hour or over.

I will now assume that as the train approaches the caution signal S the engineer pushes the plunger of a penalty valve Z..

Valve L will then shift to the'left,

then be released and valve X will remain in its left-hand position as long as magnet J remains de-energized. The-piston chamber of the high speed valve L is then connected with atmosphere through pipe 47, cavity 69 of valve X, pi e 70*and an orifice 71 of re stricted area. Pipe 70 is also opened to atmosphere through one or more of the ports 72, depending on the actual speed of the train, provided that this speed is 35 miles per hour or more. Pipe 47 is connected, however, with a timing reservoir 73, through pipe 73, so that valve L does not shift to the left until after a period of time which varies inversely as the actual speed of the train. This time interval is so adjusted, by properly proportioning the areas of ports 72 and the volume of reservoir 73, that the train will be brought to a stop by a brake application due to valve K,at approximately the same point, irrespective of its initial speed, provided the latter is between 35 and miles per hour.

As soon as relay F reverses, magnet J becomes energized reversing valve 41 to charge the timing reservoir 82 from main reservoir through pipe 46, valve 41 and pipe 75. After valve L shifts to the left,.

the piston chamber of valve U is supplied with fluid pressure from the main reservoir through 46, valve 41, pipe 75, cavity 53 in valve L, and pipe 54. It follows then that valve L remains in its right-hand position as long as magnet J M remains energized. If now the actuahspeed of the train exceeds 35 miles per hour, brake application valve K will be actuated, because the piston chamber of this valve will be connected with at mosphere through pipes 56 and 57 cavity 77 of valve L, pipe 76 and valve 43. The train may proceed, however, at 35 miles per hour or less without incurring an automatic application of the brakes.

I will now assume that the train passes resistance M in block B--C at a" speed greater than 15 miles per hour, and that the epgineer takes no action. Magnet J M then becomes de-energized, thereby opening the piston chamber of valve 1) to atmosphere through pipe 54, cavity 53 in valve L, pipe 75, valve 41, pipe 80, and restricted orifice 81. Pipe 80 is also opened to atmosphere through one or more of the ports 78 depending on the speed of the train. Owing to the timing reservoir 82 which is connected with pipe 75, valve 1) will not shift until the expiration of an interval of time which is inversely proportional to the actual speed of the train, so that the train will be brought to a stop at'ap'proximately the same point from any initial speed between. 35 and 15- miles per hour. When valve L shifts, the p ston chamber of valve K will be connected wlth atmosphere through pipes 56,v 57, and

58, cavity 59 in valve 1 pipe 82, cavity 83 of valve X, pipe 84, and a penalty valve Z. An automatic application of the brakes Wlll, consequently, occur regardless of the speed of the train. If, however, the engineer operates the plungerof valve Z while passing resistance M the exhaust passage just traced will be closed at valve Z so that the air pressure will build up in the chamber of valve Z to hold this valve closed as long as X or L are reversed, and the brakes will not be applied unless the speed of the train exceeds 15 miles per hour. In the event that the speed does exceed this value, the piston chamber of valve K will be opened to atmosphere through pipes 56, 57 and 58, cavity 59 of valve L pipe 60, and low speed valve 43 I will now assume that while the train is moving at less than 15 miles per hour, relay F- becomes energized in normal direction. The consequent energization of magnet J will cause air to be supplied to the piston chamber of valve X, through pipe 46, valve 41, pipe 50', cavity 51, pipe 65 and pipe 65, Valve X will, therefore, return to its initial position, whereupon air'will be supplied to the high speed valve L, through the body of valve X and pipe 47. Air will also be supplied to the piston chamber of valve L through valve 41, pipe 50, cavity 51, pipe 52, cavity 53 and pipe 54. The parts of the apparatus will thus be restored to the positions in which they are shown in the drawing. a

Qne important feature of the structure shown in Fig. 2 is the cavity 66 of valve K which is included in the path from the piston chamber of valve X to atmosphere through penalty valve Z. When valve K moves to brake-applying position, this path is closed at chamber 66, and so the engineer is unable to suppress a brake application resulting from his failure to observe and act upon a caution signa after such brake application is initiated.

It will be seen from the foregoing, that in each form of apparatus embodying my invention, means are provided for causing an automatic application of the brakes upon passing a caution signal, unless the speed to proceed at a low speed up to and past the stop signahprovided that the engineer takes the roper action at the proper time.

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

Having thus described my invention. what I claim is:

1. Railway traflic cont-rolling apparatus comprising means on a train for imposing a low speed limit, means on the train for im posing a medium speed limit, a high speed magnet and a medium. speed magnet, means controlled by said magnets ,for rendering both of said speed limiting means ineffective when the high speed magnet is energized so thatthe train can then travel at a speed above said medium limit. and for applying the brakes when the high speed magnet becomes de-energized. and manually controllable apparatus for preventing such brake application and rendering said medium speed limiting means efi'ective when the high speed magnet becomes de-ener gized and the medium speed magnet becomes energized provided that such apparatus is set into operation prior to the de-energization of the high speed magnet.

2. Railway traffic controlling apparatus comprising apparatus on a vehicle controlled from the trackway for giving proceed. caution and stop indications. means controlled by said apparatiis for permitting the train to travel at high speed when the apparatus indicates roceed and for imposing a low speed limit when the apparatus indicates stop, means controlled by said apparatus upon changing from proceed to caution indication for applying the brakes, and manually controllable means for suppressing such brake application and imposing a medium speed limit when said apparatus changes from proceed to caution indication.

3. Railway traflic controllingapparatus comprising vehicle carried means controlled from the trackway for permitting high speed under traffic conditions which render such speed safe, and for applying the brakes upon a change to traffic conditions requiring a medium speed, and manually controllable means on the vehicle for preventing said brake application and imposing a medium speed limit if set into operation prior to said change of trafi'ic conditions.

4. Railway traflic controlling apparatus comprising a trackway divided into blocks, signals for the blocks each adapted to indicate stop, caution and proceed, a vehicle, governing means on said vehicle controlled from the trackwa-y and set into operation on passing a caution signal for causing an automatic application of the brakes, and manually controllable apparatus also on said vehicle for suppressing said automatic brake application and imposing a medium speed limit provided said apparatus is set into operation before passing the caution signal.

5. Railway traflic controlling apparatus comprising a trackway divided into blocks,

signals for the blocks each adapted to indicate stop. caution and proceed, a vehicle, governing meanson said vehicle controlled from the trackway and set into operation on passing a caution signal for causing certain speed restrictions. and manually controllable apparatus also on said vehicle for suppressing said speed restrictions and imposing less severe speed restrictions if said apparatus is set into operation before passing the cantion signal.

6. Railway traflic controlling apparatus comprising a high speed relay and a medium speed relay carried on a vehicle, means controlled by said high speed relay when energized for permitting the vehicle to travel at high speed. means controlled by said medium speed relay when the same is energized and the high speed relay is de-energized for iniposing a low speed limit on the vehicle, a stick relay. a pick-up circuit for said stick relay including a back contact of said high speed relay and a manually operable circuit controller. a holding circuit for said stick relay including a front contact of the stick relay and a front contact of the medium speed relay. and means for imposing a medium speed limit on the vehicle when said medium speed relay and said stick relay are energized.

7. Railway traffic controlling apparatus comprising a high speed relay and a. medium speed relay carried on a vehicle, means controlled by said relays for permitting high speed when the high speed relay is enerized. for imposing a low speed when the iigh speed relay becomes de-energized and the medium speed relay becomes energized, and for causing the vehicle to stop when both relays become tie-energized. a stick relay, a pick-up circuit for said stick relay including a back contact of said high speed relay and a front contact of said medium speed relay and a normally open manually operable circuit controller. a holding circuit for said stick relay including a front contact of the stick relay and a front contact of said medium speed relay, means for imposing a medium speed limit on the vehicle when said medium speedrelay and said stick relay are both energized. a second stick relay, a pickup circuit for said second stick relay including a back contact of said medium speed relay and said manually operable circuit controller. a holding circuit for said Second stick relay including a front contact thereon and a back contact of said medium speed relay, and means for imposing said low speed limit on the vehicle when said second stick relay is energized and said .medium speed relay is de-energized.

8. Railway traiiic controlling apparatus comprising signals located in the trackway each capable of giving a restrictive and a non-restrictive indication, means on a vehicle controlled from the trackway for governing the speed of the vehicle in accordance with the indications given by said signals, means on the vehicle normally set into operation upon passing a signal giving a restrictive indication for stopping the vehicle, means under control of the driver of the vehicle for suppressing the action of said stopping means and rendering said first-mentioned means effective, and means controlled by said stopping means when set into operation for rendering said means under the control of the driver inefiective.

9. Railway traffic controlling apparatus comprising signals located in the trackway each capable of giving a restrictive and a non-restrictive indication, means on a vehicle controlled from the trackway and 1101'7.

mally set into operation upon passing .a signal giving a restrictive indication to'stop the vehicle, means under the control of the driver of the vehicle for suppressing the action of said stopping'means and permitting the vehicle to proceed at a speed corresponding to the indication given bythe s gnal, and means controlled by said stopping means when set into operation for rendering said means under the control of the driver inefiective.

10. Railway traiiic 'controlling apparatus comprising means for supplying a plurality of alternatin currents-to the track rails, means controlled by traiiic conditions in advance for reversing the relative polarity of one of said currents under caution conditions and for discontinuing the supply of one of said currents under stop conditions, vehicle carried apparatus requiring the constant supply of energy from the trackway to prevent a brake application, said a paratus being responsive to the reversal 0 relative polarity of said one current by applying the brakes if the speed is above a given low value, and to the cessation of one current by applying the brakes at any speed, and means under control of the engineer for preventing a brake application upon reversal of said one current if the speed is not above a given medium value and for preventing a brake application upon the cessation of one current if the speed is not above said given low value.

11. Railway trafiic controlling apparatus com rising means for supplying a plurality of a ternating currents to the track rails,

12. Railway traflic controlling apparatus comprising vehicle-carried means controlled from the trackway for causing certain speed restrictions upon a- .change from a, more favorable to a less favorable traflic condition, and manually operable apparatus on the vehicle for suppressing said speed restrictions and imposing less severe speed restrictions if said apparatus is set into operation before the change of traffic condition occurs.

13. Railway trafiic controlling-apparatus comprising vehicle-carried means controlled from the trackway for causing certain speed restrictions upon a change from proceed to caution trafiic conditions, and manually operable apparatus on the vehicle for suppressing said speed restrictions and imposing less severe speed restrictions if said apparatus is set into operation before the changeto caution traffic condition occurs.

14:. In a train speed control apparatus, the .combination with mechanism for imposing one of a plurality of different train speed limits according to the setting'of the track signal, of means under the control of the engineer for permitting a higher train speed limit upon passing a signal indication.

15. In a train speed control, apparatus, the combination with mechanism for imposing different train speed limits, of means operated by the engineer for causing said mechanism to impose the normal train speed limit upon passing a signal indication, said mechanism operating to impose a lower train speed limitfif the engineer fails to act.

16. In a train speed control apparatus, the combination with a mechanism controlled by a track signal indication for imposing difl'erent train speed limits, of means controlled by the engineer and operating jointly with the signal ipdication for imposing one train'speed limit, said mechanism operating to impose a lower train speed limit, in case p the engineer fails to operate said means.

17. In a train speed control apparatus, the combination with a mechanism for imposing difierent train speed limits and operated upon passing a given signal indication for imposing a low speed limit, of means operated by the engineer upon passing said signal indication for causing said mechanism to impose a higher train speed limit.

18. In a. train speed control apparatus, the combination with a mechanism for imposing difi'erent train speed limits and operated upon passing a caution signal for iml posing a low speed limit, of means actuated by the engineer upon passing saidcaution signal for causing said mechanism to impose a higher speed limit corresponding with the caution indication.

19. Railway trafi'ic controlling apparatus comprising "ehicle-carried means controlled from the trackway for automatically applying the brakes upon a changefrom a more favorable to a less favorable-traffic condition if the speed of the vehicle is above a given low limit, and manually operable apparatus on the vehicle for preventing said low speed restriction and permitting the vehicle to proceed at a higher speed without incurring an automatic application of the brakes.

20. Railway traflic controlling apparatus comprising vehicle-carried means controlled from the trackway for automatically applying the brakes upon a change from proceed to caution trafiic conditions if the speed of the vehicle is above a given low limit, and manually operable apparatus on the vehicle for preventing said low speed restriction and permitting the vehicle to proceed at a higher speed without incurring an automatic application of the brakes.

21. Railway trafiic controlling apparatus comprising trackway signals controlled in accordance with traffic conditions, vehicle carried means controlled from the trackway and normally operating when the vehicle passes a signal, indicating caution to impose a more severe speed restriction than is required by such signal indication, and means on the vehicle operating to remove said speed restriction and impose the restriction required by such signal indication if the engineer takes suitable action to indicate recognition of the signal indication.

22. Railway trafiiccontrolling apparatus comprising vehicle-carried means controlled from the trackway for imposing a low speed limit upon a change from a more favorable to a less favorable trafiic condition, and means on the vehicle operating to remove said low speed limit and impose a higher speed limit if the engineer takes suitable action to indicate recognition of the change of tl'afiic conditions.

23. Railway traffic controlling apparatus comprising means on a train for imposing a fixed speed limit under a given condition of traffic, and apparatus under control of the engineer for permitting a higher speed limit under said given traflic condition.

24. The method of controlling railway traflic which consists in automatically imposing. on a train passing a restrictive signal a lower speed limit than is required by such signal, and removing such speed limit and imposing the speed limit required by the signal if the engineer acknowledges the signal by suitable action. a

In testimony whereof I aflix my signature in presence of two witnesses.

' LLOYD V. LEWIS.

Witnesses:

A. HERMAN WEGNER, E. P. CRUM.

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