US1210210A - Automatic train-control system. - Google Patents

Description

S. D. RODGERS.

AUTOMATIC TRAIN CONTROL SYSTEM.

APPLICATION FILED APR. 24. I915. 7 1,210,210. Patented Dec. 26,1916.

3 SHEETS-SHEET I.

NH FQIJQ FIG 1 FIG. 3

1NSULA7-70N INSULATIDN will 1 4 WITNESSES INVENTOR S. D. RODGERS. AUTOMATIC TRAIN CONTROL SYSTEM.

. km 6 V 12 my ay Q 6 m 8km m 2 W T 0 Q, s? Q Q. m b: 1 W m mm R- Q 9 m mwh WWI-1R. D1 WW M m w, M 8% r m ,Q\ A v @m Q ,1 m @W -\N\ m Q m a GWN W 1 WITNESSES S. D. RODGERS. AUTOMATIC TRAIN CONTROLSYSTEM. APPLICATION Him APR. 24. m5.

3 SHEETSSHEET 3- INVENTOR Patented Dec. 26,1916.

- To all whom it may concern.-

STATES PATENT OFFICE.

STEWART I); RODGERS, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR OF ONE-FOURTH I TO CLARENCE G. HILIDRETH,

ao'romarrc OF PITTSBURGH, PENN SYLVANIA.

TRAIN -CON TROL SYSTEM;

M Specification of Letters Patent.

Patented Dec. 26, 1916.

Application filed April 24, 1915. SeriaI No. 23,710.

Be it known that I, STEWART D. RODGERS,

a resident of Pittsburgh? in the county of Allegheny and State of ennsylvania, have invented a new and useful Improvement in Automatic Train-Control Systems, of which the following is a specification.

This invention relates to automatic train control systems for use with any block system of railway signaling. Its object is to prevent the engmeer from disregarding the signals, and to automatically bring the train to stop in case'of dangerion'the block ahead even though the engineer does not see or disregards the signals.

A further object is to control the speed ofthe train by setting the brakes in case of danger ahead, and automatically releasing the brakes as soon as the train gets down to the predetermined slow speed.

The system operates entirely upon the closed circuit principle, so that any failure of the system will at once be made known to theengineer so that it can be remedied.

The invention comprises the arrangement of circuits and apparatus arranged andconnected as hereinafter In the accompanying drawings, Figurel is a diagrammatic View of a section of track constituting a single block showing the im provements applied thereto; Fig. 2 is a diagrammatic view-of the apparatus on the locomotive and tender; Fig. 3 is a detail view of one of the relays used along the track; Fig. 4 is a detail view of the automatic brake valve which is employed for controlling the engine speed; and Fig. 5 is a detail View of the semaphore circuits and switches.

The system can be used in connection with any system of block signaling, and Fig. 1 illustrates merely such ch made in the standard block signaling system, without showing'the circuit arrangement for operating the semaphores of standard block signals. I In Fig. l the direction of the train is indicated by the arrow 1. In applying the improved system there is inserted at the end of each block two short sections of rail marked' described and claimed.

.wires or bonds 9 3, comprising a inserted in one of the rails a similar insulated rail section 3, and still farther in advance there is inserted in the another similar rail section 4. t each of trolling box or relay, shown in detail in Fig.

solenoid 5 whose core carries a switch bridge member 6 adapted to cooperate with two terminals 7 and 8, one of which, such as 7, is connected through with the two adjacent op osite rail.

I the nsulated rall sections is placed a con- 1n advance of the end of the bloclr'there is ends of the contiguous rails 12 and'the other 4 of which is connected by with the short insulated rail section. Consequently all of the cally connnected, while the sections 2, 3 and 4 may be also connected electrically to rails 12 by closing the circuitsthrough the contacts 7 and 8. Normally, the solenOids 5 are energized so that the'bridge piece 6 establishes contact between the terminals 7 and 8 so that whatever current is flowing in the rails 12 will also be conducted by wire 10 to the short insulated sections. The rails 12 are always supplied with current, as in all standard block systems.

The solenoids 5 are controlled from the semaphores 13 and 14. These latter will Roe controlled from the block signaling system in the ordinary way now in vogue, and which has not been illustrated in the;drawings, but the latter merely show the additions which are made thereto. These addi 'tic-ns comprise a suitable source of current,

having its other pole connected to contacts 17 and 18 associated lso associated with these semaphores are two other contacts 19 and 20, all of such contacts being so placed that when the semaphores are in normal position, that is, upright to indicate a clear track, switch members 21 and 22 on said semaphores connect the contact 17 to the contact 19 and the contact 18 to the contact 20. M

The contact 19 is connected by circuit wire 23 with one terminal of the solenoid coil located at the distant or caution insulated rail section 4, the other terminal of which is grounded such as by beingconnected to one of the rails 12. The contact 20 is connected by circuit wire bond or wire 10 l 24 to the sole- I noid coils located adjacent to the two insulated rail sections 2 at the end of the'block, or at the home or stop station, and also with the solenoid coil at 3 all of said solenoids being in series in the circuit wire 24, and the last of the coils being rounded, such as by being connected to one of the rails 12, as shown in Fig. 1.

The operation of this part of the apparatus is as follows: When the track is clear and the semaphores are standing upright, both circuits are closed at the semaphores, so that all of the solenoids at each of the insulated rail sections 2, 3 and 4 are energized and maintain closed circuit between the of the locomotive or tender.

terminals 7 and 8 at each of these stations. If now a train is in or enters the block in advance at such a distance as to actuate only the green semaphore 13, this will drop, as in Fig. 5, thus breaking the circuit between terminals 17 and 19 and hence deenergizing the solenoid located adjacent to the insulated rail section 4, whereupon the core of said solenoid will drop and break the circuits between terminals 7 and 8 at this station, so that the insulated rail section becomes, electrically dead. Should however the train in the preceding block be in such position as to actuate both of the semaphores to indicate danger, the circuit will be broken not only between contacts 17 and 19,but also between contacts 18 and 20, so that the solenoids adjacent-to each one of the insulated rail sections become denergized, allowing their cores to drop, breaking the circuits between the terminals 7 .and 8 and thus interrupting flow of current to each-of the insulated rail sections 2, 2, 3 and 4, so that each of these rail sections is now electrically dead.

The foregoing are all of the changes made in the track arrangement, these being merely additions to the usual block signaling systems, and the purpose is to render the rail section 4 electrically dead when the semaphore 13 shows caution and to render all of the rail sections 2, 2, 3 and 4 electrically dead when the semaphores indicate danger. All of the other apparatus is mounted on the 10- comotive and tender and will now be described.

The locomotive or tender, preferably the tender, carries a yielding shoe or contact member 26 which slides along on top of the rail and is connected to the circuits on the locomotive. As shown, this shoe is connected by circuit wire 27 to one terminal of a magnet coil 28, whose other terminal is connected by circuit wire 30 with one terminal of magnet coil 28, whose other terminal is connected by circuit wire 27 to a shoe or contact member 26 on the opposite side Cooperating with the magnet 28 is an armature 31 connected as shown to the circuit wire 30 and serving as a circuit closer to cooperate with the insulated rail section a contact 32 in a circuit containing a magnet coil 33 and a circuit wire 34 leading to the reversing switch 35. Cooperating with the magnet 28* is a similar armature 31 also connected to the circuit wire 30 and serving as a circuit closer to cooperate with a contact 32 ofa circuit wire in which is a magnet coil 33 connected to circuit wire 34 also leading to the reversing switch 35. The armatures 31 and 31 normally occupy the positions shown in Fig. 2, that is, away from the contacts 32, 32. When the coils 28, 28 are denergized, as hereinafter described, said armatures are pulled down to and held against their contacts by light springs 31", whose tension is slightly less than the pull of coils 28, 28, so that when said coils are later energized, as hereinafter described, the armatures are returned to normal positions, as in Fig. 2. The Source of current on the locomotive comprises two l atteries 37 and 37 of equal value and similar arrangement,two batteries being employed so that if one becomes exhausted the other is available. The negative poles of these batteries are connected through circuit wire 38 with the circuit closing armature 39 of a magnet 40, said armature cooperating with a contact 41 connected to one terminal of the magnet 40, whose other terminal is connected at the point 38 to the circuit wire 30. The first named terminal of the magnet is also connected to contact 42 with which'cooperates a resetting switch 43 electrically connected to the wire 38.

The positive poles of both batteries are connected through wire 44 with the reversin switch 35, and in the circuit from each battery to the reversing switch is placed an automatic control switch 45, which comprises a pair of solenoid coils 46 and 46" whose cores carry circuit-closing contacts 47 and 47 respectively, connected in series with the coils of the solenoids and cooperating with stationary contacts 48 and 48 connected respectively to the positive poles of the two batteries. The cores of the two solenoids are connected through the pivoted rocking levers 49 and surrounding each core between the coil of the solenoid and said lever is a spring, marked respectively 50 and 50*. As shown in Fig. 2, the circuit from battery 37 is closed, at the contacts 47 and 48, and as long as the current from this battery is of sufiicient strength the core of solenoid 46 will be held down, compressing the spring 50. The circuit from the other battery is open at contacts 47*, 48. When, however, the battery 37 becomes exhausted the strength of solenoid 46 decreases, until the spring 50 is able to retract its core, therebyrocking the lever 49 and depressing the core of solenoid 46 sufliciently to bring its contact 47 against the stationary contact 48*. This at once establishes the circuit from battery 37,

72, which is ture 71 out of engagement hausted the other is automatically switched.

into the circuit.

he reversing switch 35 comprises three switch blades 52, 53 and 54 respectively.

The switch blade 52 is connected directly to the battery circuit wire 44 and when in one position cocperates with a contact '55, and when in the reverseiposition with contact 56, both of which have connected thereto the ground wire 57. The switch blade 53 when in one position connects with contact 58 which is connected to circuit wire 34*, and also with contact 59, and when in its opposite position it connects with contact 60 which is connected to circuit wire 34:, and also with contact .61. The blade 54 when in one'position connects with contact 58 to which is connected the circuit wire 34,

and also with contact 59, and when in its opposite position it connects with contact 60 to which is connected the circuit wire 34, and also with contact 61. The contacts 59 and 61 are -cross connected together, and contacts 59 and 61 are also cross connected together. Contact 61 is connected through circuit wire 62 with the ground wire 5.7, and in this circuit is placed a bell or other audible signal 63, and a lamp or other visual signal 64 and also a push button 65 by means of'which said circuit can be opened. Likewise, the contact 61 is connected through magnet 36 and circuit .62 with'the ground. wire 57, and in this circuit there is also a bell or other audible signal 63, a lamp or other visual signal 6 1 and a push button 65.

The ground wire 57 is divided, having two branches 57 and 57 both. of which are grounded, such as through the wheels of the locomotive or tender at 58 and 58 branch 57 a is a solenoid coil 66, for actuating the brake application and release valve 67, hereinafter described. In the branch 57 is a magnet coil 68 connected by wire 69 to a contact 69 adapted to co6perate with a hand switch 70 in a circuit leading to the ground 58*. Coiiperating with the magnet 68 is an armature 71 arranged also to act as a circuit closer in conjunction with contact connected to the ground wire branch 57 Armature 71 is in turn controlled by armature 73, which coiiperates with" theinagnet 36 in the circuit wire 34;, and which armature 73 is normally held away from the core of magnet 36 such as by spring 7 1, and in position-to lock the armawith the contact 72. When, however, magnet 36 is energized the armature 73 is drawn' against its core, thereby releasing the armature 71 and allow- In the ing it to drop onto contact 72, so as to establish a circuit from the ground wire branch 57 through the armature 71 and thence by wire 75 to the speed control switch 76, which coiiperates with a contact 77 connected by wire 78 to a contact 78 also coiiperating with switch 70. The speed control switch 76 is controlled by a centrifugal governor 80 of the usual type, which is driven by suitable bevel gears 81 and sprocket 82 from some portion of the running gear of the locomotive or tender, such as from an axle. In case the engine is running at a high speed the centrifugal governor holds the switch 76 on contact 77, thus maintaining ground at 58, but when the speed of the train slows down materially the centrifugal governor moves the switch 76 oif the contact 77 so as to break this ground. A supplemental contact 7 7 is provided with which the switch contacts in case the chainor other operating connection for driving the governor fails, or when the train is at a stand-still, or practically so, to again establish ground at 58*.

The brake controlling valve mechanism is shown in detail in Fig. 4. This comprises a suitable casing connected at its upper end through pipe 85 with the train pipe 86. In pipe 85 is a cook 85 for cutting out the automatic control. In the casing is a diiferential piston mechanism comprising the small piston 87 and the large piston 88 rigidly connectedtogether through the stem 89. The piston 87 carries a spring pressed valve 90 normally seating against the port from pipe 85 and sealing the same. At the side of the casing at its upper end are a number of vents numbered 91, 92 and 93 respectively, located atdiflerent levels and controlled by the piston 87. The vents 91 and '92 are controlled by suitable blow-off valves 94 and 95 respectively, set to blow off to difi'erent degrees. When the piston 87 lowers it first uncovers vent 91, allowing the air pressure to blow oil to a certain predetermined degree; when the piston 87 lowers still farther to uncover vent 92 it permits the pressure to blow off to a lower pressure; and when the piston 87 drops suificiently to uncover Vent 93 the pressure from the train pipe can escape slowly without any throt tling. The chamber below the piston 87 and the chamber above piston 88 are connected through a small passage 96 through the stem 89 so as to relieve the lower face of the small piston and the upper face of the large piston from pressure, and which also retards the movement of said pistons and prevents them from hammering the cylinder heads. The chamber below the large piston 88 is connected through pipe 100 to av chamber 101 in the lower part of casing 102. In this casing is a partition 103, and the chamber 104 above said partition is connected by pipe 105 to the train pipe, preferably to the 'all of the short sections branch pipe 85. The partition 103 is'provided with a seat 106 for a valve 107 carried by a stem 108 which is normally biased, such as by spring 109, to seat the valve 107 and close communication between pipes 105 and 100. The upper end carries an armature 110 cotiperating with the magnet 66 in the ground circuit 57*. The lower end of stem 108 projects down through an opening in the" bottom of the casing 102 and is provided with a passage 111 so located that when the piston stem 108 is elevated, as shown in Fig. 4, it is entirely within the chamber101, but when said piston stem 108 is lowered to seat the valve 107, the upper end of said passage is within and its lower end without the chamber so that said passage forms a communication from the chamber 101 to the atmosphere. This passage may be throttled to retard the exhaust by a set screw 111 Normally, the magnet 66 is energized, thus holding the armature 110, valve stem 108 and valve 107 elevated or in the position shown in Fig. 4. In this position communication from chamber 101 to the atmosphere is cut off, but communication is established between pipes 105 and 100. Consequently, the train pipe pressure acting against the lower face of the large piston 88 will overbalance similar pressure acting on the upper face of the piston 87, with the result that the differential piston mechanism is lifted to the position shown in Fig. 4 to close all of the vents 91, 92 and 93, and also seat valve 90 against the port from pipe 85. Whenever, however, magnet 66 becomes deenergized, the armature 110, valve stem" 108 and valve 107 drop, with the result that communication between pipes 105 and 100 is cut off and chamber 101 isvented to the atmosphere through groove 111. This slowly vents the chamber underneath the large piston 88, until the pressure above the small piston plus the weight the differential piston mechanism to drop. In its down movement the piston 87 first uncovers the vent -91, allowing a certain amount of pressure to blow out therethrough. As the differential piston mechanism lowers still farther, vent 92 is uncovered, thus allowing still more pressure to escape, and when the piston 87 is fully down the vent 93 is opened, so as to allow pressure to escape to a still further degree. The mechanism therefore gradually reduces train pipe pressure and brings about a gradual application of the brakes, in the ordinary manner of application of automatic air brakes, as will be readily understood, and thereby slows down the train.

The operation of the system as a whole is as follows: When the track is clear and of rails are alive the current carried therein enters both contact of the valve stem'108 1 'the oncoming train reaches of the parts causes shoes 26 and 26 and passes to the battery 37 or 37 (whichever is in circuit through switch mechanism 45) which battery is connected with its positive pole through wire 44 to switch blade 52, to contact 55, to contact 56 and'through wires 57 57, through the magnet 66 of the brake control valve to the ground at 58. Consequently, current normally flows through the ground branch 57 keeping the magnet 66 energized and holding the brake control valve in the position shown in Fig. 4, that is, with the vents from the train pipe to the atmosphere closed; The ground branch 57 is normally open at the-contact 72 and also at thecontact 69 and switch 70. Should now a train be in or enter the next preceding block so as to cause the semaphore vane 13 to drop and break the circuit through the magnet 5 located adjacent to-the' insulated rail section 4, this rail section becomes dead, and when this caution station the shoe 26 passes upon the dead rail section 4, as a consequence of which the circuit from shoe 26 to thejunction point 38 becomes momentarily dead. vThis de-- energizes magnet 28 allowing armature 31 to momentarily drop onto contact 32. The circuit now is from the positive pole of the battery 37 or 37 through wire 44, to blade 52 of the reversing switch, thence to contact 55 and to Wire 57', said current dividing and one portion still flowing through branch 57* and, coil 66 to ground, while another portion flows through green slgnal lamp 64,

bell 63,circuit'wire 62, to contact 61, and

thence through the cross connection to contact 59, through blade 54 of the reversing switch to contact 58', and thence through wire 34, coil 33, contact 32-, armature 31, wire 30, coil 40, contact 41, armature 39 and wire 38 to the negative pole of the battery.

Consequently, the engineer is warned by the ringing of hell 63 and the flashing, of the green signal light to run with caution. The audible and visible signals in the cab therefore prevent the engineer from disregarding the semaphores, or act as an auxiliary warning in case of darkness or fog which makes the semaphores invisible. The signals are maintained until the engineer presses button 65 and opens the circuit through coil 33, thereby allowing coil 28 to return the armature 31 to its first position, shown in Fig. 2, ready for another signal operation. If the train in the next block is so close as to cause the actuation of both semaphore vanes 13 and 14, the circuit to all of the track magnets 5 will be broken and all of the rail sections 2, 2, 3 and 4 are dead. When the oncoming trainreaches the danger station, the shoe 26 coming in contact with the dead rail section 3 will interrupt the circuit between shoe 26 and the junction point 38", whereupon the magnet 28*. is momentarily de'nergized, allowin armature 31 to drop onto contact 32 and this establishes a battery circuit from the plus pole of the battery through wire 44 through the reversing switch to wire 57, whence said current will divide as before, except that the return portion will pass through bell 63* and red signal light 64, and thence by circuit wire 62 to contact 61, thence through the cross connection to contact 59, through switch blade 53 to contact 58 and thence to wire 34:, coil 33, contact 32, armature 31, wire 30, coil 40, contact 41, armature 39 and wire 38 pole of the battery. The condition so far therefore, is the same as before described, except that the red signal light instead of the green signal light is flashed in the engineers. cab. The signals are maintained, as in the case of the red signals, until the engineer presses button 65*. In addition to this the battery current also actuates magtrain net 36, thus drawing armature 73 from underneatharmature 71, allowing the-latter to drop onto contact 72 and establish a battery circuit through the ground wire 57 through contact 72, armature 71, wire 75, ground switch 76, wire 78, contact 78, and switch to ground at 58*. The ground branch so established, being devoid of any magnet coils has a lower resistanw than the ground branch 57 in which is the magnet coil 66; consequent y, the coil 66 becomes denergized allowing the armature 110 thereof to drop together with valve stem 108 and valve 107, thus interrupting communication from pipe'branch 105 to pipe 100 leading to the face of the large piston of the diflerential piston mechanism, and also venting the chamber 101 to the atmosphere. This results in the dropping of the differential piston mechanism and the venting of the train line. so as to gradually apply the brakes, as hereinbefore described. Consequently, at the danger station the engineer is not only advised of the danger by the ringing of a bell and the flashing of a red light in the cab, but if he fails to heed these the brakes are automatically applied so as to slow down the train. The application of the brakes continues until the train has been slowed down sufficiently, as determined by the centrifugal governor mechanism. As long as the train continues at a dangerous speed the centrifugal governor holds the switch blade 76 on contact 77, thereby maintaining the ground circuit through branch 57 as above described and continuing the application of the brakes. When, however, the speed of the train has been reduced to such a degree as has been determined by the centrifugal governor mechanism, the switch blade 76 moves 0d the end of contact 77, thus breaking the ground connection" through branch 57". whereupon battery current will again to the negative find ground through the branch 57 and magnet 66, energiz ng the latter to lift the armature 110, valve stem 108 and valve 107, so as to interrupt the vent to the atmosphere from the lower face of the large piston of the difl'erential piston mechanism, and again establish communication from the train pipe branch 105 to pipe 100, and cause the difi'erential piston mechanism to rise and interrupt the vent from the train pipe. When the train comes to a complete stand-still the switch 76 will move onto supplemental contact 77" and again establish ground through the branch 57. To release the'train brakes the engineer moves switch 70 to contact 69 and momentaril energizes coil .68, thus lifting armature 7 and allowing armature, 73 to move outwardly and lock armature 71. This breaks circuit 57* as before, and allows the train pipe pressure to build up and release the" brakes. Switch 70 is then restored to original position. If the oncoming train approaches to the end of the block, both shoes 26 and 26 come over the dead rail section 2, and in this event both magnets 28 and 28 become dee'nergized, and both .the armatures 31 and 31 drop. Consequently, the battery circuit through the coil 40 is also interrupted and the armature 39 also drops, breaking the battery circuit quence of which the flow of battery current to the ground through magnet 66 is completely interrupted, allowing the armature 110, valve stem 108 and valve-107 to drop and bringing about the application of the brakes and bringing the train to a standstill. When only one of the shoes 26 or 26 is on a dead rail section the magnet 40 does not become deenergized because current. can still flow from the live shoe through this coil and thence through the battery to ground. To reset the armature 39 it is merely necessary to close the switch 43, so that with one or the other of shoes 26 or 26 upon a live rail section a circuit will be established through the coil 40, causing it to draw the armature 39 against stop 41.

In the ground wire 57 is placed a small resistance 112, shunted by a lamp 113 to serve as an indicator of the conditions of the circuits on the locomotive. As long as this lamp is burning it indicates that the circuits are in working order. It is necessary to reverse the switch 35 only when reversing the train, as will be readily understood.

Suitable fuses 115 are placed in the battery circuits at both sides of the battery, and suitable control switches 116 are also placed in the battery circuits.

The control mechanism described is supand energizes coil 66 at contact 11, as a conse plementary to the ordinary block signaling I system, and prevents the engineer from disregarding the ordinary semaphore signals,

both by audible and visible signals. in the cab, when reaching both the caution and the danger stations; and also provided for the control of the speed of the train by an application of the brakes in case the engineer does not heed the danger signal. This system can be used in connection with any standard block system and requires but slight modification of the track arrangement,-the system being concerned largely with the equipment on the locomotive. It operates upon the closed circuit principle, so that any derangement of it will produce an open circuit which will be at once indicated in the engineers cab, that he can no longer rely upon it.

What I claim is 2- 1. lrain control apparatus, comprising a brakecontrolling valve, a magnet arranged to normally hold said valve out of operation, a signal circuit, and means for controlling said magnet, comprising circuits on the train and including a portion of the track, said last named circuits being adapted on a first interruption to close said signal circuit and on a succeeding interruption to deenergize said magnet and allow the valve to operate.

2. Train control apparatus, comprising a brake controlling valve, a magnet arranged to normally hold said valve out of operation, a signal circuit, means for controlling said magnet, comprising circuits on the train and including a portion of the track, said last named circuits being adapted on a first interruption to close said signal circuit and on a succeeding interruption to de'elnergize said magnet and allow the valve to operate, and means for energizing said magnet to release the brakes.

8. Train control apparatus, comprising a brake operating device on the engine, normally closed circuits including a portion of the track for controlling said brake operating device, two signal devices on the engine, a normally open circuit through each of said signals, means for closing one of said open circuits on a first interruption of said normally closed circuit, and means for closing the other open circuit on a succeeding interruption of said normally closed circuit.

4. Train control apparatus, comprising a brake operating device on the engine, normally closed circuits including a portion of the track for controlling said brake operating device, two signal devices on the engine, a normally open circuit through each of said signals, means for closing one of said open circuits on a first interruption of said normally closed circuit, and means for closing the other open circuit on a succeeding interruption of said normally closed circuit and for simultaneously causing actuation of said brake operating device.

5. Train control apparatus, comprising a train pipe, valve mechanism operated by so that he will be advised cuits on the train andincluding a portion of the track and arranged when interrupted to allow said controlling device to operate and cause said successive reductions in train pipe pressure.

6. In a train control system, brake controlling mechanism, comprising a cylinder communicating with the train pipe and provided with a plurality of exhaust openings, and a piston in said cylinder operated by train pipe pressure and arranged to successively uncover said openings.

7. In a train control system, brake controlling mechanism, comprising a cylindercommunicating with the train pipe and provided with a plurality of exhaust openings, and differential piston mechanism operated by train pipe pressure and including a piston in said cylinder arranged when operated to successively uncover said openings.

8. In a train control system, brake con trolling mechanism, comprising a plurality of cylinders communicating w1th the train pipe, connected pistons in said cylinders, one

arranged when operfrom the means for when the train speed is reduced, w'hereby 1 said mechanism 1s again held out of operation.

10. Train control apparatus, comprising brake operating mechanism, circuits for controlling said mechanism and including shunt circuits through the two track rails, two signal devices on the engine, means for establishing circuits through said signal devices when the shunt track circuits are broken, means for opening the main controlling circuit when both of said shunt track circuits are broken to thereby cause operation of the brake operating device, and a speed controlled governor on the train controlling a shunt ground circuit from the main circuit for preventing effective action of the main controlling circuit on the brake operating mechanism until the engine speed is reduced.

11. Train control apparatus, comprising engine,

brake operating mechanism, circuits for controlling said mechanism and including shunt circuits through the two track rails, two signal devices on the engine, means for establishing circuits through said signal devices when the corresponding shunt track circuit is broken, and means for opening the main controlling circuit when both of said shunt track circuits are broken to thereby cause operation of the brake operating device.

12. Train control apparatus, comprising brake operating mechanism, circuits for controlling said mechanism and including shunt circuits through the two track rails, a caution signal and a den er signal on the means for esta lishing circuits through said signals when the corresponding shunt track circuit is broken, and means arranged when said danger signal is energized to actuate said mechanism and apply the brakes to reduce the engine speed.

13. Train control apparatus, comprising brake operating mechanism, circuits forcontrolling said mechanism and includingshunt circuits through the two track rails, a caution signal and a danger signal on the engine, means for establishing circuitsthrough said signals when the corresponding shunt track circuit is broken, and means arranged when said danger signal is energized to actuate said mechanism and apply the brakes to reduce the engine speed and when theengine speed is reduced to then release the brakes. j; V

14. Train control apparatus, comprising brake operating mechanism. circuits for controlling said mechanism and including shunt circuits through the two track rails, a cantion signal and a danger signal on the engine, means for establishing circuitsthrough said signals when the corresponding shunt track circuit is broken, means arranged when said danger signal is energized to actuate said mechanism and apply the brakes to reduce the engine speed, and a speed controlled governor arranged when the engine speed is reduced to actuate said mechanism to release the brakes.

15. Train control apparatus, brake operating mechanism, circuits for operating said mechanism and including shunt circuits through the two track rails, a caution signal and a danger signal on the engine, means for establishing circuits through said signals when the corresponding shunt track circuit is broken, and means arranged when said signal devices areenergized simultaneously to open the main controlling circuit and actuate said mechanism to apply the brakes and stop the train.

16. Train control apparatus, comprisingbrake operating mechanism, circuits for controlling said mechanism and including shunt circuits through the two track rails, a cantion signal am a danger signal on the en tion signal and a danger comprising v gine, means for establishing circuits through said signals when the corresponding shunt track circuit is broken, means arranged when said danger signal is energized to actuate th mechanism to apply the brakes and reduce the train speed, and means arranged when said signals are energized simultaneously to open the main controlling circuit and actuate said mechanism to apply the brakes and stop the train.

17. Train control apparatus, comprising brake operating mechanism, circuits for controlling said mechanism and including shunt circuits through the two track rails, a causignal on the englne, means for establishing circuits through said si als when the corresponding shunt track clrcuit is broken, means arranged when said danger signal is energized to actuate said mechanism and apply the brakes until the train speed is reduced and then actuate said mechanism to release the brakes, and means arranged when said signals are energized simultaneously to open the main controlling circuit and actuate said mechanism to app i y the brakes and stop the train.

18. rain control apparatus, comprising brake operating mechanism, circuits for controlling said mechanism and including shunt circuits through the two track rails, a caution signal and a danger signal on the engine, means for establishing circuits through said signals when the corresponding shunt track circuit is broken, means arranged when said danger signal is energized to actuate said mechanism and apply the brakes to reduce the train speed, a speed controlled governor arranged when the engine speed is reduced to actuate said mechanism and release the brakes, and means arranged when said signal devices are energized simultaneously to open the main controlling circuit and actuate said mechanism to apply the brakes and stop the train.

. 19. Train control apparatus, comprising automatic track signal mechanism having a caution position and a danger position, brake operating mechanism on the engine, circuits for controlling said mechanism and including shunt circuits through the two track rails, two signal devices on the engine, and means arranged when the signal mechanism moves to caution or danger position to establish a circuit control on corresponding signal devices on the engine.

20. Train control apparatus, comprising automatic track signal mechanism having caution and danger positions, brake operating devices on the'engine, circuits for coning signal on the engine, and means arranged when said danger signal is energized to actuate said mechanism and apply the brakes.

21. Train control apparatus, comprising automatic track signal mechanism having caution and danger positions, brake operating devices on the engine, circuits for controlling said devices and including shunt circuits through the two track rails, a cau-- on the engine, means arranged when said signal mechanism moves to caution or danger position to establish a circuit through the corresponding signal on the engine, means arranged when said danger signal is energized to actuate said mechanism and apply the brakes, and a speed controlled governor arranged when the engine speed is reduced to actuate said mechanism to release the brakes.

22. Train control apparatus, comprising automatic track signal mechanism having caution and danger positions, brake operattion signal and adanger signal ing devices on the train, circuits for controlling said devices and including shunt circuits through the two track rails, a cantion signal and a danger signal on the engine, means arranged when said signal mechamsm moves to caution or danger position to establish a circuit through the corresponding signal on the engine, means arranged when said danger signal is energized to actuate said mechanism and apply the brakes until the train speed is reduced, and means arranged when said signal devices are energized simultaneously to open the main controlling circuit to actuate said mechanism and stop the train.

In testimony whereof I have hereunto set my hand.

STEWART D. RODGERS.

Witnesses Emma: L. Hrim, 'GLENN H. LERESCHE.

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