US1765355A - Automatic train control and signal - Google Patents

Description

June 17, 1930. c. w. BREWSTER AUTOMATIC TRAIN CONTROL AND S IG-NAL Filed Jan. 6, 1916 9 Sheets-Sheet 1 R nw/suron CizarZes WBrewster WITNESS W: C

nrronufrs June 17, 1'930. c.,w. BREWSTER 7 AUTOMATIC TRAIN CONTROL AND SIGNAL Filed Jan. 6, 1916 9 Sheets-Sheet 2 !ii m. w Wm WV 3 n my .8 4 s Q 0 N z, I w i .7 3 M A TTORIVEYS June 17, 1930. c. w.- BREWSTER 1,765,355

AUTOMATIC TRAIN CONTROL AND SIGNAL I Filed Jan. 6, 1916 9 Sheets-Sheet WITNESS INVEIV TOR W C W 44/5 fig? Charles WBrewszfier A TTOR/VE Y8 June 17, I930. c. w. BREWSTER 1,765,355

AUTOMATIC TRAIN CONTROL AND SIGNAL Filed 191 9 Sheets-Sheet -4 A TTOR/VEYS June 17, 1 930.

C. W. BREWSTER AUTOMATIC TRAIN CONTROL AND SIGNAL Filed 1916 9 Sheets- Sheet 5 ,9 INI/E/VTOR Charles WBre ws liar A Z//////// I'QI til m WITNESS afcw A TTOR/VE Y8 June 17, 1930. c w BREWSTER 1,765,355

AUTOMATIC TRAIN CONTROL AND SIGNAL Filed Jan. 6, 1916 9 Sheets-Sheet 6 WITNESS INVE/V r01? Charles WBrews tar A TTOR/VE Y8 June 17, 1930. c, w, BREWSTER 1,765,355

AUTOMATIC TRAIN CONTROL AND SIGNAL Filed ll- 1916 9 Sheets-Sheet '7 wlmsss Z67 267 "INVENTOH W C, W A; f luz'rles WBrewste/v" A TTORNEYIS" June 17, 1930. c. w. BREWSTER 1,765,355

AUTOMATIC TRAIN CONTROL AND SI [GNAL Filed Jan. 6, '1916 9 Sheets-Sheet 8 I WITNESS A TTOR/VE Y8 June 17, 1930. C. W. BREWSTER 1,765,355

AUTOMATIC TRAIN CONTROL AND SIGNAL Filed Jan. 6, 1916 9 SheetsSheet 9 a mfi WITNESS Q Q l/VVE/VTOR 91% a, W Ulzarles Wfirewster Patented June 17, 1930 UNITED STATES cHAnLEs w. BREWSTE F nnw YORK, n. Y.,. ssrei 1 oa, BY Miisnn' assreivms'n rs,

T0 SPRAGUE SAFETY CONTROL AND SIGIQAL A CORPORATION or VIRGINIA inUToMATIo TRAIN concur 01L Ann SIGNAL Application filed January 6, 1916, Serial No; 70,579.

This invention isa system of train control wherein provision-is made for meeting the various conditions of service calling for freedomrin the movement of the vehicle under normal or full speed while advising the driver or motorman of the condition of the track ahead; further, should the vehicle attempt to approach an occupied block ahead at too great a speed, the progress of the vehicle towards said occupied block is automatically reduced to a' lower speed, means being provided so that the distance intervening between-the vehicle and-the occupied block will determine the speed at which the vehicle may travel, or in other words, the speed of a following vehicle while approaching a preceding vehicle is reduced'proportionately to the distance separating the two said vehicles, and

' thereafter the driver or motorman is. permitted to proceed up to the entrance of an occupied block at said reduced speed, but should a vehicle attempt to enter an occupied block ahead, then the progress of the vehicle towards said occupied b-lock is first automates ic -ally stopped,and then the driver or motorman is enabled to again start'the vehicle but when progress is resumed the system is such that the speed of the vehicle is automatically cut down to slow speed without any possi- V bility of an increase in such speed so that the vehicle can tra-vel in an occupied track section under conditions assuring a maximum of safety'both to the vehicle ahead and to the following vehicle, such progress at slowspeed being the only speed at which said following vehicle can proceed within said occupied block or until the entire block is traversed, so that said following vehiclewill in due season arrive at or pass one of the magnetic interferences hereinafter described, whereupon the signal indication on the vehicle will have changed from danger to caution, or from caution to clear or the vehicle will have been brought to a full stop, but should the signal! indication be changed so as to justify the vehicle proceedingunder a clear signal, then the mechanism which limits the vehicle to slow speed or any controlled speed will be automatically cut out of service so that the so vehicle may proceed at full speed; further,

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provision is ma'de for the display of a signal constantly to the viewof the river and pref,- erably in the. cab or motormans boX, the-sige nal so displayed being of a character to denote the condition of the track ahead, thus a clearlsignal is shown to the driverwhen there is no vehicle within signalling distance, or should a vehicle occupy the track within a predetermined distance of the following vehicle, thenvthe character of the signal is changed to denote caution, but should the following vehicle approach a vehicle ahead so that a relatively shorter distance separates t-he'tw-o vehicles, then the signal on the following vehicle is changed to denote danger; further, should the signal on a following vehicle change from clear to caution, or from caution to danger, the driver is given an opportunity of manually reducing the speed of said following vehicle, but in the event that the speed is not reduced after the vehicle has proceeded a certain distance subsequent to the change of signals, then means are brought into service whereby the desired speed reduction is effected automatically and the speed of said vehicle cannot be thereafter increased by any effort of the driver, nor can it be ining to effect the desired signal and speed control without, however, requiring physical contact between the movable equipment on the vehicle and the stationary track equipmen't, such freedom from physical contact between the'tracl: equipment and the vehicle equipment resulting in an air gap intervening the two said equipments, whereby the liability of disarrangement due to physical contact is wholly obviated and the influence of the track equipment upon the vehicle equipcontrolled, as a result of which it is not possible for the driver to interfere in any manner whatsoever with the automatic application of the brakeexcept that the driver may still further apply the brakes soas to make a further speed reduction or to bring the vehicle to a full stop.

The track equipment is of such a nature that each block or section requires a low consumption of current from a suitable source to maintain each particular block or section in.

a condition for service, thus obtaining economy in current consumption, but when a particular block or section is occupied by a vehiole, then the full energy from the available source of supply is brought into condition for use automatically, provided, however, that the track ahead is not occupied by a vehicle within signalling distance of the particular block so occupied. i

The track equipment includes, preferably, a closed track circuit for each block, although an open track circuit may.be utilized, the

closed track circuit'being preferred for they reason that should a rail or conductor be broken or a batterybe exhausted then the signal on the vehicle is displayed at danger and said vehicle broughtto a stop.-

7 According to this invention, the track equipment for each block or section embodies a relay and a source of direct current energy l0-1O of Figure 8.

in a normally closed track circuit the latter including also a high resistance relay, the latter being positioned at or near one end of the block, whereas the first named relay and the energy source are at or near theopposite end of the block, as a result of which organization I am enabled to secure accuracy in the operation of the signals, notwithstanding the equipment may be subjected to the influence of extraneous currents or to the existence of current leakagefacross the insulations of the sectional track rail or between the parallel rails of the track, and it is possible,also, to

. install the track equipment utilizing direct current at substantial economy as compared with the cost of equipment dependent for its operation upon the energy of alternating current.

In the drawings Figure 1 is a diagram illustrating my system of train signal and control, the dotted llnes representing a preceding vehicle in one Figure 3 is a horizontal sectional plan view, 7

the plane of the section being indicated by the dotted line 33 of Figure .2. V

F igure 4c is a view partly inelevation and, partly in section of the circuit maker and the magnetic interference,.said circuit maker being carried by the moving vehicle, Whereas the magnetic interference constitutes a part of the track equipment.

Figure 5 is a sectional plan view of the circuit maker and the magnetic interference, the plane of the section being indicated by the irregular dotted line 5 hot Figure 4.

Figure 6 is a sectional elevation oi theautomatic speed governor adapted to be driven by the rotary motion oi an axle on one of the movingvehicles, said governor operating primarily to control speed of the moving vehicle when it is within signalling distance of a preceding vehicle.

Figure 7 is a vertical section on theline 77 of Figure 6.

Figure 8 is an elevation of a solenoid enibodying a retarding device and adapted for use in connection with the caution signal or with the danger signal.

Figure 9 is a vertical section on the line- 9 on Figure 8. Figure 10 is a horizontalsection'on the line Figure 11 is a horizontal section on the line 11'11 of Figure 8. V

Figure 12 is a section,'partly in elevation, of a valve mechanism associated with the air brake on a moving vehicle, certain parts of said air brake system beingillustrated diagrammatically.

Figure 13 is a vertical section of the solenoid which indirectly controls the brake mechanism of Figure 12 and which controls, also, a circuit which'includes a vehicle propelling motor.

Figure 1-1 is a vertical sectional elevation through one of the solenoids connected in ser es with. the rails of one block for controlling theenergization or" the track magnets of certain blocks in the rear.

Figure 15 is a horizontal section on the line 15-15 of Figure 14. y

Figure 16 is a vertical section of another solenoid connected acros the rails constitut ing one block so as tov be shunted by the presence of a vehicle, occupying said block.

Figure 19 is a plan v1ew of the cut-out sole- 1101(l of Flgure 18.,

, FigureQO is a diagram of a vehicle equip-' ment for one car of a train adapted to control theentire train from the front end of the lead- 7 ,ing car when moving in one direction and operating, also, when running in the opposite direction to transfer the s gnal control to the other end of the train, that is, the car which was previously the leadingcar now becomes the rear car of the train, and the signal and automatic brake control are automatically changed to the aforesaid leading car. 7

In the system diagrammatically represented in Fig. 1, the track is shown as embodying a continuous rail a and a sectional rail a, the parts ofsaid sectional rail being electricallyinsulated at a so asto produce a succession of blocks each of any required length, three of saidrblocks A B C and a part of a fourth block D being represented. Each block is equipped as follows At the point where a vehicle enters each block is positioned a solenoid-relay 10, the coil of which is connected directly to the rail a of said block. vA second solenoid 11 is connected also to the rail a, preferably at or near the point where a vehicle emerges from each block, and fromthis solenoid 11 a conductor 12 leads to the continuous rail a. and from said rail (0 leads a conductor 18 to the negative pole of battery 14, from the positive pole of which a conductor 15 leads to the solenoidrelay 10, thus establishing a closed track circuit for the current to flow from battery 14, conductor 15, solenoid-relay 10, rail a,ele'ctrically conductive interference 30, solenoid 11, conductor 12, a part of rail a, conductor 13 to the negative pole of battery 14. The two solenoids 10, 11, included in the closed track circuit are energized under normal conditions by current from battery 14, so that with both the coils 10, 11, connected in series with battery 14 as shown, there will be a minimum flow of current through solenoid 1O andsaid minimum low of current through said solenoid 10 holds the core thereof normally in a position to complete the circuits through certain track magnets of blocks positioned rearwardly of the particular block as will be presently described. At the same time the coil of solenoid 11 holds the core thereof in a raised positionand tree from certain contacts in circuits leading to the track magnets of the block with which the solenoid 11 is directly associated. The two solenoids thus JGI'fOTII] distinct functions with respect to the block to which said solenoids are connected; thus, solenoid 11 opens andcloscs the circuits to the track magnetswhich are associated with the same block so that said solenoid 11-is a local make and break device for said particular block, thus acting as a local circuit closer, whereas the other solenoid 1O is the signal controlling element for the. track magnets in blocks positioned rearwardly and for definite distances of the particular block underconsideration as isto beshown. It

maybe stated that with a vehiclepresentin 11, whereupon the core'll drops by gravity a particular block, the flow of current from and the switch member 11 of said core makes certain contacts so as to connect the track magnets electrically with the return rail a as will appear hereinafter. In this invention there is at alltimes displayed in the view of the engine driver or motorman a. signal of one character or ,another for indicating the COHClltlOILOf the track ahead; thus, with a clear track fora certain distance or for a certain number of blocks ahead, the si nal 0mm approaching vehicle'indicates clear; with a vehicle in a block a certaindistance ahead the signal on I the approaching vehicle is changed automatically to cut out the clear signal and to display-caution signal when the following vehiclereaches a certain distance in the rear of a preceding vehicle, but with the following vehicle proceeding. to a point still closer to the preceding vehicle, then the signal is once more changed on the following vehicle so as to cut out the caution signal and to display a danger signal. The territory thus protected by signals comprises what may be termed a control zone, in that the cabsignals for this territory together with the automatic braking provided for is under the control of track conditions in the advance 'zone 01 similar characteristics. Such azone for example isillustrated in Fig. 1 by the adjacent blocks C, B. v

To the attainment of these ends, it is preferred to equip each block with two rows of magnets adapted to be so controlled as to influence the vehicle equipment for the display of signals according to the condition of the track and to the distance separating a following vehicle from a preceding vehicle.

The-number and arrangement of the track 'magnets in each block 1s dependent in a certain measure upon the proximity or remoteness ofthe particular block from a point of congestion, so called, by which term is meant any condition of the track at which trains may behkely to congregateor to stop,"

such e. g. as a station, either for express trains or local trains, a switch or a crossover, or a curvein the track. Thus in blocks remote to'the point of congestion, the number of track magnets may be at alminimum, say F1139 two in a row, whereas in blocks closer to the point of congestion, the track magnets in each of two rows are increased in number so as to actuate the cab signal control mechanism an increasing number of times the nearer the vehicle approaches the point of congestion.

A salient feature of this lnvent on is the provision of means for automatically con trolling the speed of a vehicle so that it is reduced without any elfort upon the part of the driver; in fact, is not within the drivers control. Briefly, the signals displayed in the cab are dependent upon the condition of the track, whereas the speed of the vehicle is dependent upon the signals displayed in the cab.

- of the preceding blocks controlled through the solenoids 10 as will hereinafterbe shown.

'As shown, each solenoid 10 includes a plungor or core 18 provided with wiping contacts 19, 20, 21 electrically insulated at 22 and cooperating with the circuit contacts positioned intermediate the conductors leading from the battery 14 to the track magnets in a certain number of blocks positioned in the rear of the particular block adapted to be occupied by a vehicle, the arrangement be ing such as to bring about the following results; with a particular block occupied by a vehlcle, the current from battery 14 associated with that block is shunted out of the circuit closing solenoid 11 by the wheels and axle across the rails a a so as to establish an mcreased flow of current in the controlling solenoid 10, thus moving the core 18 and shifting the contacts lt), 20, 21, to interrupt the circuits as lollows:first, to the magnets 17 of the first block i. e. the block immediately in the rear of the occupied block as well as the last magnet 17 at the exit of the second block in the rear; second, to interrupt all the magnets 16 in the first and second blocks in the rear, and, third, the circuit to the last magnet 16 in the third block in the rear. It is thus apparent that, underthe cond tions recited, the solenoid 1O performs certain mportant functions in interruptng the circuits to the magnets 17 positioned in the first and second blocks in the rear for nfluencing the danger signal and, also, in-

terrupts the circuits to the magnets 16 in the second and third blocks in the rear to influence the caution signal, whereby there may be said to be an overlap in the relation to each other of the caution and danger controlling magnets in the second and'third blocks in the rear. Thus inrespect to the control zone above referred'to the said last magnet 16 at the exit of the third block to the rear when deenergized collaborates with other instrumentalities later to bereferred to, to effect the display of a caution signal at the entrance to the protected control zone, and the said magnet 17 at the exit of the sec ond block to the rear when deenergized and with like collaboration eilects the display of a danger signal at an intermediate point in the said protected control zone.

It is preferred'to wire the magnets as follows 7 From thebattery conductor 15 a lead23 runs to'contact 19 of the first solenoid 10, thence it runs at 23 to the magnets 17 ofthe first block in the rear; thence at 23 to the last magnet 17 of the second block in the rear and thence at 23 to the magnets 16 (one or more) of thesecond block in the rear thence to contact 2i of the third sOlenoidlO, thence at 23? to the last magnet 16 of the third block in the rear, thus constituting a continuous lead from battery let of one block to as many blocks in the rear as it may be desired to control the signals; thus, the signal control herein shown extends rearwardly through three blocks from an occupied block and spans the control zone as above explained. It is apparent that said conductor 23, 23, 23, 23 is in eliect a continuous conductor from the positive side of the battery 14 of one block to the specified magnets 16, 17 of three blocks in the rear. When this circuit is broken by relay 1() by reason of the presence of a train as indicated by the trucks X, for example, in block A, which comprises the first half of the advance control zone, provision is made for the caution signal at the entrance to the control zone C, B, and the danger signal intermediate said control zone (C, B) as'above pointed out. With the track clear and under normal conditions, the flow of current from battery 14 of one block to certain track magnets in three blocks in the rear is interrupted because the solenoid 11 of each block is energized under said normal conditions tobreak the return connections from the specified magnets to the battery l l.

The track magnets under normalconditi.ons are thus deenergized and the circuits from the battery to the magnets are open; this is considered advantageous for the reasons that economy of current is obtained and by energizing the magnets intermittently, instead of continuously, it is possible to so wind them as to obtain an increased magnetic pull between the magnets and the elements of the" vehicle equipment.

The preceding detailed description sets forth the circuit connections from the positive side of a battery in one block, tothe magnets 16, 17 of three blocks in the rear,

under normal conditions, and it is now de sired to explain the manner of obtaining the return connections from the specified magnets to the negative side of the ba-tterywhen the particularhlock is occupied, normal conditions prevailing, and with a clear track ahead of the occupied block. In this con- 11 ction it is proper to say that the return connections of one block are the same as similar comicct-ions for every other block of the system, and that the electrically continuous rail a or the ground is utilized as a common return. T he return circuit connections of each block include the circuit closing solenoid 11,

the moving part 11 of which is adapted to make electrical connection with a group of contacts 24; from one Contact 24 a'conductor '25 leads to the final magnet 17 of the block;

from another contact leads a conductor 26 to the remainder of the magnets 17 in said block; fromanothercontact 2a a conductor 27 leads to the final magnet 16 in the rowin said block; from another contact 24 a conductor 28 leads to the remainder of the magnets 16 in said block, and from the last contact 24 a cupied blocks with which said magnets are associated.

The track magnets 16, 17, in the series of blocks and energized by current from the batteries 14 as described, producein the track a magnetic circuit or means possessing magneticpermeability, the fields of which magnets emanate lines of force so as to influence the armatures on the Vehicle equipment passing through said fields, said armatur es of the vehicle equipment and the track magnets being free from physical contact and being separated by an air gap, as before explained.

When the track is unoccupied, the magnetic field produced by the track magnets in the successive blocks is of a desired length suited to the conditions of vehicular traific, but the presence of vehicles on the track and the proximity of such vehlclesto each other produces automatically a change or variation in the operative length. of the track circuit. The presence of vehicle X in block A shunts current from solenoid 11 by the wheels and axles of said vehicle X in contact with the rails, and this influences solenoid 10- so that the latter interrupts the circuit to track magnets 17 of the first block in the rear of the occupied block and also the first magnet 17 at the exit. of the second block in the rear,

vehicles.

and at the same time the solenoid 10 interrupts all the magnets 16, in the first and secend blocks in the rear of the occupied block,

and also interrupts the last magnet 16 in the third block in the rear of said occupied block.

The solenoids 10, 11, cooperate to effect a variation in the length of the magnetic track circuit, and such operative length of the magnetic track circuit is dependent upon the dis tance intervening the two vehicles upon the,

track, one of which vehicles precedes the other within a determined distance, for the reason that the following vehicle moving in a block or blocks in rear of the occupied block so influences the solenoids 11 of the blocks that on the continued forward movement of said following vehicle the solenoids .10 are in like manner successively influenced and thus reduce the operative length .ofthe magnetic circuit afiorded by the track mag-.

nets'according to, and in proportion to, a decrease in the distance separatlng the two Further, the magneticcircuit in the track is formed bytwo series of track magnet-s 16,;

17. in the successive blocks, one series of magnets,as 16, in the successive blocks may be in service or de-energized dependent'upon the proximity of the two vehicles so that the magnetic circuit formed by the magnets 16 is of a certain length, whereas the magnetic circuit formed by the other series of track magnets 17 in. successive blocks may be in 7 service or de-energized according to the proximity of the two vehicles so to result ina magnetic circuit also of a. desired length, which two magnetlc circuits formed by the two series of magnets 16, 17 and their com-' plemental solenoids and batteries are, or may be inorerlapping relation to each other so as to eti'ect the control of the signals and the brakemechanism of the vehicle equipment in a desired. order.

It is understood, furthermore, that the track circuit is grounded by the presence of' rolling stock, such as a vehicle Y or Z upon the rails a, a and within a given block or blocks thereof, said traclr circuit or magnetic circuit including stationary magnets 16 or 17, or 16 and 17, extending in series substantially throughout a different block or blocks fromthat in which the ground may be eficcted. Said track magnets emanate lines of forceand constitute a magnetic field through which are adapted to travel certain elements, as 16?, 17 and 47, of an equipment on a moving vehicle, which elements are in cluded in a circuit or circuits of said vehicle equipment.

, Again, the solenoid 10 is so connected in circuit with the track magnets as to normally de-energize the latter, but the solenoid 11 is influenced by the presence of a vehicle on the track so that it shunts current through the solenoid 10 and simultaneously therewith establis'hes the magnetic field of said track magcent to or at a suitable distance from the point at which a vehicle leaves the block. Various forms of the circuit interrupting devices may be employed, but as shown this part is a magnetieinterference occupying such position in the track that as a vehicle passes the device the latter is interposed in the magnetic field of a certain magnet on the vehicle so as toshunt the field of said magnet and thereby change the signals should the condition of the track warrant such changeor to operate the brake control to a full stop should the track rconditions justify the same. The magnetic interference is in the form of a metallic bar, preferably of magnetizable soft iron extending upwardly from the track near one of the rails, said bar being electrically connected with the rail a, so as to be in circuit therewith. Should it happen that in the course of repairing the track, the workman omits to replace the magnetic interference 30. provision is made forinterrupting the circuit through rail a by dividing andinsulating the rail at a at a suitable distance from the exit of the block, said interference 30 being bonded to the rail a in any suitable way so as to render the rail a electrically continuous around the break a.

As is well known, serviceof the battery 14 occasions diminished energy, but to provide a margin of safety in maintaining each block in a serviceable condition, means are employed to interrupt the local track circuit through solenoids 10, ll of said block when the battery reaches a certain minimum strength. Accordingly, a cut out 31 is in terposod in the battery circuit, said out out including a coil connected in a shunt around the battery and the core or plunger of said coil controls a trip The coil of the cut-out is wound to a certain resistance, and when current from the battery becomes weakened to a point where thecoil. is not suiiiciently energized to overcome the action of a mechanical rctractor included as a partcf the cutout, then the core or plunger is actuated'to operate the trip and thus break the battery circuit for the particular block with which the battery is connected, as will appear more fully in connection with one detailed form of the cut-out hereinafter described.

1 he vehicle equipment includes signals 33, 34, 35 indicating clear, caution and danger respectively. energized from a common battery 36, or other source of electrical energy.

There is a direct lead 37 from the negative side of the battery to the signals, said lead including a suitable resistance 38.' All the signals are under the control, primarily, of

solenoids 39, 40, the latter being controlled by armatures 16 17? carried on the vehicle and the signal-circuit maker 47 said arniatures being in turn controlled by the track magnets l6, 17 of the track equipment.

Solenoid 39 is shown as a coil and a plunger, the latter being equipped with a moving part 39 which carries a plurality of switch members 41, 42, electricallyinsulated therefrom. In a similar manner, solenoid is a coil and a plunger, the latter having a,

of the vehicle equipmentunder certain conditions of operation.

The signal circuits are as follows I For the clear slgnal 33 the circuit includes a conductor 48 extending from the positive side of battery 36 to the switch member 43 of solenoid 40; from said switch member 43 a conductor 49 leads to switch member 41 of solenoid 39, and from the switch member,41 a conductor 50 leads to the lamp denoting clear signal 33. For the caution signal 34,

the circuit includes conductor 48, switch member 43, conductor 49, and when the armature 39 of solenoid 39 is dropped, the conductor 49 to a conductor 51 leading the lamp of caution signal 34. The circuit for danger signal 35 includes conductor 48 to which is connected a conductor 52, and when the armature 40 of solenoid 40 is dropped, the switch member 44 0f said armature bridges the gap between conductors 52, 53, the latter leading to signal lamp 35. r

Under normal conditions there is displayed a clear signal by current from battery 36 flowing through lamp 33. 'To this end, the circuit maker 47 is energized by current from battery 36 flowing through branch conductors 48 and 37 to the coils of said circuit maker, whereby the armature 47 is attracted to close the following circuits:A branch 48 is tapped onto conductor 48 and leads to armature 47*; from the armature 47" conductors 54, 55, lead respectively to switch member 42 of solenoid 39 and to switch member 44 of solenoid 40; from switch member 42 a short conductor 56 leads to the coil of solenoid 39, and from this coil another short conductor 37 is branched ontothe return connection 37 runmm; to the negative side of the battery; from the switch memberll a short conductor 57 leads to the coil'of solenoid 10, from which coil leads a short conductor 37branched on the return battery connection 37 to 'conductor 56 is tapped a conductor 58leading to the' switch member 15 of'armature" 16 and from this switch member 15, a conductor 60 extends to switch member 416, from which member 4l6 a conductor '59 leads to and is connected with conductor 57 of solenoid coil 40, and connected-with said conductor 60 at a point intermediatethe switch members 15,

' 16, isa conductor 61 leading-to branch'conductor 18 thence to conductor 48 and thence to positive side of the battery 36.

As hereto-fore stated, the clear signal 33 is normally displayed with a clear track ahead of the vehicle carrying the signal equipment. This is due to circuit maker 17 holding the armature 47 to close the circuit between battery 36 and solenoids 39 and 4 which in turn complete the circuit between battery 36 and lamp 33, the current flowing as follows:-- from battery 36', conductor 48, switch member 13 of solenoid 40, conductor 419, switch member 41, conductor 50, lamp 33, and conductor 37, throughresistance 38 back to batter'y. As will be noted the solenoids 39, 40, hold their cores in raised positions for the members 41, 13 to close the signal circuit.

It should be stated thatiwhen no vehicle is present in a block, the magnets 16, 17 of that block are de-ene'rgized because solenoid 11 of that block is energized so'as to hold armature 11* away from contacts 24, thus opening the circuits to the magnets '16, 170i each unoccupied block; but as a vehicle Y equipped as described moves along the track and the armatures 16 17 are brought within the fields of the magnets 16, 17, said armatures 16 17 are moved by the magnetic pull of said magnets 16, 17, in the event of the magnets bein energized by current from the batteries 1 1 in the proper blocks of the track ahead oi said moving vehicle, Y. Assuming that normal conditions prevail, that the track ahead is clear, and that the vehicle Y is traveling in block D toward the right with a clear signaldisplayed, the action is as follows The wheels and axles of the vehicleY shunt the current out of solenoid 11,'allowi-ng armature 11? to drop against contacts 2% of the particular block occupied by the vehicle Y. This armature thus completes the return connection from'magnets 16, 17 of the occupied block to the batteries 14 of block A and block B respectively, as follows:'l/Vith vehicle Y in block D the last magnet 16 of said block D opposite interference 30 is energized by current flowingfrom battery 14 of block A through conductor 15, switch member 32 of tout-out 31, conductor 23, switch member 19 of 29 tappedon conductor 12 block solenoid in block A, conductor 23, switch memberQO of solenoid 10 in block B, conductor 523 switch member 21 of solenoid 10 in block C, conductor 23 magnet 16 in block D, conductor 27 in block Dvto armature 11 in solenoid 11 block D, conductor"29 "of block D tappedonto conductor 12 toreturn rail ('0 and thence to conductor '13 to battery 14 of block-A. Last magnet 1701 block D opposite the said interference 30 is at the same time and under the same conditions energized as followsz-From' battery 1 10f block B current flows through conductor 15, switch member 32 of cut-out 31in bloclr B, switchmember 1901 solenoid 16in bloclrB, conductor 23 switch member of sole- 'noid 10' in bloclrC, conductor 23, to magnet 17 A in block D, thence by the return connections includin conductor block D, switch member 11 oi solenoid 11 block D, conductor D, thence by return rail a to conductor .13 block 13, to battery 1% in the latter block. The mag nets 16 and 17 at the rear of block D immediately behind the magnets 16 and 17 opposite the interference have their circuits under the control respectively oi blocks B and G of the protected control zone shown in Fig. 1 apparent from the drawing. For these magnets 16 and 17 to be energized, therefore, it is necessary that the said protected control zone be clear. As will later appear more fully, these magnets 16 and 17 at the rear of block D immediately behind the interference 30 act as a resetting means for certain train-carried equipment including the solenoids 39 and 40 respectively. For the said track magnets thus to function the forward train X must have proceeded in its travel out of theprotected control zone C, B and into the advance control zone, for example, as shown in Fig. 1.

As the vehicle nears theexit from a block, the armatureslti 17 pass through the magnetic fields of track magnets 16 17 and at the same time the circuit maker 17 assumes such relation-to the magnetic interrupter 30 that the latter is brought into the magnetic lield of said circuit maker 17; These operations have noapparent effect upon the clear signal 33 should the track ahead be clear and the signal system be in normal condition.

Assuming that a vehicle X occupies the block A and that a vehicle Y with a clear s gnal displayed is approaching the exit point of block D, a change of the signal indication from clear to caution is eiiiected on said vehicle when it passes the magnetic interrupter 30 and the magnets 16, 17 nearest the exit of said block D. This change oi sigw nal is brought about by the'vehicle X in block A shunting the current in the manner heretofore described so as to interrupt the flow of current from battery 14 of block A to the track magnet 16 of. block' D, h'ence as the ice its

armature 16 on the vehicle Y passes the de-- will not be attracted for an appreciable interval of time because of the presence of the interference 30 between the armature 47 a and the polesof the magnet 47, and thus a spring 47 pulls the armature 47 away from the poles of the magnet so as to break the circuit between the battery 36 and solenoids 39, 40, but the armature 17 a is attracted by the track magnet 17 so as to complete the circuit from battery 36 direct to coil of solenoid 40 during the interval of interruption of circuit maker 47 by the interrupter 30, at which period the solenoid 39 is tie-energized, permitting armature 39 to drop, interrupting the flow of current to clear signal 33 and establishing the flow of current from battery 36 to caution signal 34. As the vehicle passes the interference 30 in block D, and immediately thereafter the magnetic pull of magnet 47 attracts armature 47 so as to close the battery circuit to the switch member 44, and solenoid 40 remains energized until the next interruption, the solenoid 39 being de-energized at this time because the battery circuit to signal solenoid 39 is interrupted at switch member 42, and solenoid 39 remains tie-energized until'the vehicle Y progresses sufficiently to bringthe armature l6 within the field of an energized track magnet 16 however far said energized magnet 16 may be located from the track magnet at which the signal changes take place. Assuming that vehicle X remains inblock A, the vehicle Y now passes into block C, and is free to'proceed therein until it reaches the interference 30 of said block C without any change of signal indication, caution signalbeing constantly displayed because magnets 16 of block C are deenergized. As the vehicle Y passes over the final magnets 16, 17 of block 0 and the interference 30 of said block, 0, the said interference is interposedbetwe en the armature 47 and the poles of circuit maker 47 so as to interrupt the circuit from battery 36 to switch member 44 and solenoid 40, and as the armature 17 of said vehicle Y passes over a de-energized magnet 17 in block C, at the same instant that the circuit maker 47 interrupts the circuit it follows that the armature 17 is not attracted by said de-energized magnet 17 of block C, hence armature 40 is dropped and the circuit to battery 36 is opened at switch member 43 to both the clear and caution signals 33, '34, and current is directed by switch member 44 to flow through the danger signal 35.

The danger si nal is thus displayed in vehicle Y so that Y must by the operation of a brake mechanism to be hereinafter described come to a stop in block B and remain in said block B or near the end thereof next, to -1nterference 30 in said block B, this condition prevailing until a change takes place in block A. As X moves out'of block A and into the next preceding block, the magnets 17 of block B become energized and the armature 17 is attracted so as to complete the circuit from battery 36 to the coil of solenoid 40, thus cutting outthe danger signal and displaying the caution signal. WVithblock A vacated by the forward movement of vehicle X into the block next ahead, or as it maybe referred to,

the next preceding block, vehicle Y with the caution signal displayed is free to move into block A, but when X moves into the second block ahead'and with Y in block B, then thesignal indication of Y is changed from cautlonto clear.

It will be noted that the magnets 16, 17 of the track equipment and the armature 16317 and 47 a of the magnets in the vehicle equipment are tree from physical contact, an air gap intervening between the ariniatures on the vehicle equipment and said track magnets and the magnetic interference when the vehicle travels on the track in proximity to said track magnets and the magnetic interference.

i will now proceed to describe the mecha-' nism whereby the speed of a vehicle moving within blocks at predetermined distancesin the rear of an occupied block is automatically reduced. Each vehicle is equipped. with a speed governor 65 of any suitable type adapted to be dr ven from an axleof said vehicle, said governor operatlng dlrectly on a switch 4 66 adapted to make electrical connection with the series of contacts 67, 68, 69, 7 0, 71, whereof the contact 67 is directly connected, by a conductor 67 branched on to the lead 48, with the positive side of battery 36, it being noted that the reduction of speed of the moving vehicle is to be effected by the application of a brake to the vehicle and by shutting oil the power, to which ends I employ a solenoid- 7 2 which acts primarily to open and close the circuit from battery 36 to air-brake-control relay 73 and to cut off the power normally supplied to the controller 74. in the art, electric power is supplied from a third rail or otherwise to a motor 75 for propelling the vehicle, said motor being connected in circuit with the controller in the usual way, and the leads 76, 77, of said circuit for the motor and the controller extending to As is usual a switch member 7 8 movable with, and insulated from, the armature 7 2 attached to the plunger or core of said solenoid 72. The airebrake-control relay 73 will be described in detail hereafter, but as shown by the diagram the coil of said relay is in a circuit formed by leads 80, 81, said lead 80, extending directly to, the switch member 79 movable with and isulated from the armature of the solenoid 72 whereas the lead 81 extends from said switch member 79 to and'is tapped onto the conductor 48 to the positive side of battery 36', the return from relay 73 to the negative side of battery 36 being through conductors 82, 83, the latter beingtapped onto conductor 37 The solenoid 72 which directly influences the brake relay 73 and the controller circuit is energized by current, from battery 36 when the signal control solenoids 39, i l-0, are effective in displaying a clear signal and with the speed governor switch 06 free from the contacts aforesaid; but cooperating with the solenoid 72 are two other solenoids 84, 85, which under certain conditions open and close the circuits from battery 36 to solenoid 72. For the purpose of distinguishing solenoid 8 1 from the other solenoids it will be hereafter designated as the full stop solenoid; the solenoid 85 as the low speed solenoid, and the solenoid 72 as the brake and controller solenoid.

As shown, the'armature 84; of full stop solenoid 84 is equipped with switch members 86, 87, insulated from said armature, wherethe low speed solenoid 85 has its armature 85 equipped with other switch members 88, 89, electrically insulated from said armature.

Before describing the circuit connections for the solenoids 72, 84, 85, it is desired to state that the signal controlling solenoids 39, 40 are constructed with retarding devices, preferably in the nature of dash pots as will be hereafter fully described, for the purpose of delaying the automatic application of the brakes and the shutting oil the power so that the driver is given an opportunity, after a change of signal as from clear to caution or from caution todanger, to manually apply the brakes and to shut oil the power in order to ell'ect the required speed reduction, but should the driver neglect to perform these functions manually, then after an appreciable interval the Speed control mechanisms in their entirety act automatically either toreduce the speed within appropriate limits or to bring the vehicle to a full stop as will be hereinafter described; It will be seen that the signal control solenoid 39 is equipped with a switch member 90, operated by and insulated from the retarding mechanism of said solenoid 39, whereas with the other si nal control solenoid there are associated twoswitch members 91, 92, operated by and insulated from the retarding devices connected with said s'olenold l0.

l/Vith a vehicle in which a clear signal is displayed, moving at a hlgher speed than is permissible should the caution signal be d1s= played, the speed governor switch 66 will be 7 free from the contacts composing the group, thelow speed solenoid 85 is Clo-energized, full stop solenoid 84: is energized, and the brake andcontroller solenoid 72 is energized, the circuit connections being as follows :-Fron1 the coil or" solenoid 72 a conductor 94 leads to switch member of solenoid 85 in either of the two positions of armature 85; from switch member 88 a. conductor 96 leads to switch inember87 of solenoid 84; from switch member 87 a conductor 97 leads to and taps onto conductor 98 leading to switch member 91 of solenoid from switch member 91 a conductor 99 leads to and is tapped onto conductor 100, the latter leading to switch member 90 of solenoid 39; from member 90 a con.- ductor 101 leads to switch .member 92 oi solenoid 40; a conductor 102 is tapped onto conductor 101 intermediate the switch members 90, 92, and said conductor 102 ista-pped onto conductor 61 leading to positive side of the battery 36; the described connections completing that part of the circuit between the coil of solenoid 72 and the positivepole of said battery. The connections between the solenoid coil 72 and the negative poleof the battery 36 are constituted by a conductor 103 leading from the coil 72 to the coil of solenoid 8e; tapped onto conductor 103. is a conductor 10%- which is tapped onto eon ductor 83 and thence to the negative pole of said battery.

From the coil of solenoid 84: leads a .conductor 105, branched for one part to extend to switch member 92 and the other part to switch member 86 forming part of the circuit of relay 8 L; from switch member 92 leads the described conductor 101, thence'to conductor 102 leading as stated to the positive pole of battery 36. As shown, there 1s another connection whereby the coil of solenoid 84: is in con'iinunication with the positive side of the battery as follows :From switch member 86 of solenoid 8 1a conductor 106 leadsto the armature d7 of circuit maker 47 and thence by conductors d8", 48 and 48 to the positive side oi the battery. The negative connections of solenoid coil 84. with the battery are through conductors 103, 104, 83, 37 and 37.

Ordinarily the low speed solenoid 8 5 is (ls-energized, but the coil thereof has a direct connection through conductor 83 with the negative side of the battery 36. When energized, the coil of solenoid is connected with. the positive side of said battery as tollows:Conductor 110 which is branched for one branch thereof to have contact with switch member 89 when armature 85 is attracted whereas the other'branch of said conductorllO leads to a contact in the contact 67 the conductor 6'? leads to conduct or 48 to positive pole of the battery 36.

The operation of the speed control mecl anism in applying the brakes and shutting oil the power is dependent in a measure upon the signal solenoids, and upon the neglect or refusal of the driver, when the signal changes, to make a proper speed reduction.

Accordingly, the signal solenoids 39, 40, are connected indirectly with the governor contacts 70, 71 as follows :From contact 71 the conductor 100 leads to switch member 90 of solenoid 39. From contact 70 conductor 98 leads to switch member 91 of solenoid 40.

The operation of the speed reducing mechanism is as follows With a vehicle Y moving in, say, block D with a clear signal anl at: any speed in excess of the predeternined speed permitted when the caution signal is displayed, the governor 65 is driven and holds the switch 66 free from all the governor contacts. Assuming that block A is occupied by vehicle X and that vehicle Y is passing over the last magnets 16, 17 and interference 80 of block D as shown, it follows that the signal changes from clear to caution as heretofore described, the arn'ia-ture 89 of solenoid, 89 drops and permits a retarding device associated with said solenoid to act in a manner hereinafter described to eilcct a relatively slow movement of, switch member 90, thus giving the driver suflicic to. apply the brakes and eflect the required reduction in speed before the circuits are interrupted by switch member 90, thus resulting in a corresponding collapse of the speed gov ernor 65 and a movement of the switch (36 into electrical engagement with contacts 71 and (3?, the speed controlling mechanism herein disclosed permitting of the usual manual application of the brakes independently of the automatic action of the speed. controlling mechanism itself. Should th engine driver neglect or refuse to manually reduce the speed, then the operation of dropping ar ture 39 associated with solenoid 89 allows the retarding device of said solenoid to drop, after a short interval of time, the switch member 90 and thus inter mat the circuit between solenoid 72 and the positive side of battery 36, permitting armature 72 of solenoid T2 to drop and interrupt also the circuit connecting the brake solenoid 73 and the battery, and also to break the circuit including the controller and motor, thereby shutting off the power and applying the brakes automatically to effect the required speed reduction. W hen the brakes are applied, vehicle Y will have passed into block C, and'when the reber 8'7, conductor 96, switch member 88 of solenoid 85, conductor 9%, solenoid 72, and

thence through conductors'103, 104, 83, 37

and 37 to negative side of battery. Solenoid is thus energized and armature 72 at tracted so as to restorenormal condition to the brake solenoid 73 and to complete the power circuit.

Vehicle Y can now proceed, with caution signal displayed and under a certain predetermined speed, through block C and into block B, but with vehicle X still in block A, the signal indication on vehicle Y is again changed when passing over interference of block C so as to cut out the caution signal and display the danger signal. This change of signals is due to the dropping of armature. 40 of solenoid 40 as described heretofore, the core and retarding device of said solenoid a0 giving ample opportunity for the engine driver to effect a still further reduction of speed manually, which speed reduction actuates the governor to move the governor switch 68 into engagement withcontacts 67 and 70. Should the engine driver not exercise this precaution, the switch member 91 of said solenoid 40 opens the circuit previously established by the speed reduction mechanisms automatically brought about when the signal changed from clear to caution, and thus the connection from positive battery to the solenoid 72 is again interrupted, this time by switch member 91 of solenoid l0, de-energizing the solenoid 72 and armature 72 drops to apply the brakes and shut oil the power. The proper reduction having been made in the, speed of vehicle Y, the solenoid 72 is again energized as follows r-from positive battery through leads 48, 67, contact 67, governor switch 66, contact 70, conductors 98, 9? switch member 87 of solenoid 84, conductor 96, switch member 88 of solenoid 85, conductor 94, solenoid 72, the return from solenoid 72 being by conductors 103, 104k, 83 37 37 and negative battery. Solenoid 72 is thus reenergized to restore normalconditions to brake solenoid 78 and the motorcircuit.

It is apparent that should the vehicle Y proceed at a speed exceedin that permissible menses by the respective signals, the speed governor will be operated to interrupt the circuit required to energize solenoid 72, and thus the speed will be reduced automatically to that in correspondence with the signal condition.

'lVith block A still occupied by vehicle X, vehicle Y can proceed, with the danger signal displayed and at the properly reduced speed, to move through block B up to the interference 30, at which a visual marker may be employed for the guidance of the driver. lVith the danger signal displayed, it is apparent that the engine driver should manually bring the Vehicle Y to a full stop in block B just beforereaching interference 30, in which position the armatures 16 17 will be over the magnets 16, 17, second from the exit point of block B. Vehicle Y should re main at a full stop in the last described position until vehicle X moves out of block A when magnet 17 will be energized. This will in turn attract armature 17 on vehicle Y and will change signal from danger to caution, it being obvious that a vehicle should not pass the interference 80 with a danger signal showing. In this connection it should be observed that the interference 30 should be spaced far enough from the exit of each block to permit the automatic stop mechanism to bring the vehicle to a full stop from the maximum speed permitted by the speed control mechanismwhen the danger signal is displayed. It is evident that the minimum length of any twoadjoining blocks is determined by the distance required for the engineerto first reduce the speed and, second, to

bring the vehicle to a full stop should the signal conditions require the same.

\Vith vehicle X still in block A and vehicle Y in block B, should an attempt be made by. vehicle Y to pass interference 30 in block B, then the brakes areautomatically applied to'vehiele Y for bringing it to a full stop as follows As the circuit maker 17 of vehicle Y passes the interference 30 in block 13, the said interference interrupts the magnetic circuits of 47 as described and armature l? breaks the circui from battery 36 to solenoid 84;, whereupon armature 8 1 drops to open the circuit from battery 36 to solenoid 72, thus applyingthebrakes and cutting off the power, as a result of which the vehicle brought to a full stop before vehicle Y can pass .out of block 13.

that the coil of solenoid 85 is energized by current flowing from positive battery, eonductors 41:8, 67 governor contact 67, governor switch 66, contact 68 conductor 108, switch member 87 of solenoid 84, conouctor 110,

coil of solenoid 85 thence through con,'

ductors 88, 37 37, to negative battery. This attracts armature 85 which bridges the gap between conductor 110 of coil 85 and a conductor 115 leading to a contact in the path of armature 47 of the circuit maker 47, thence to positive pole of battery 86, thus completing the circuit of solenoid 85 as follows: From the positive side of battery 36, through conductors 18 and 48", armature 47, conductor 115, switchmen'iber 89, conductor 110, solenoid 85, back to the negative side of the battery.

The solenoid 8% is again re-energized when upon passage of an energized magnet 17, solenoid 10 is ire-energized. The pickup circuit of solenoid 8l'is then established as follows: From the positive side of battery 36,

through conductors 18, 61 and 102, through switch member 92 of solenoid 10, conductor 105, solenoid 841;. back to the negative side of the battery. I i

With vehicle Y at a full stop at the end of block B, and with solenoid energized, it is apparent that it will remain in such energized condition until vehicle Y again passes one of the interferences 80 in either a preceding block or a succeeding block. It is apparent, also, that with solenoid 85 energized as stated, the armature85 is attracted by solenoid 85 and switch member 88 bridges the gap between conductors 9 1' and 109, thus resulting in solenoid 7 2 being energized from battery 36 as follows :Battery'36,con-' ductors 458, 67, contact 6?, switch 6, contact 69, conductor .109, switch member 88 of solenoid 85, conductor 9%, solenoid 72, and thence to negative side of battery by conductors 108, 104C, 83, 37 and 37. The brakes are thus released and the motor circuit restored, the brakes being released so long as switch 66 is in contact with contacts 69, 67, the length of contact 69 relative to Contact 67 being such-that the switch 66 will bridge said contacts only when the vehicle proceeds at slow speed, but should the speed exceedthe predetermined slow speed then the governor will move the switch 66'to break the contacts and again apply the brakes. Accordingly, vehicle Y can proceed at slow speed only from block B into occupied block A,'the danger signal being constantly displayed. Should the vehicle X move. out of block A into the next preceding block ahead, vehicle Y cannot proceed in block A at a speed in eXcessof the required slow speed untilsaid vehicle Y; passes the interference 30 in block A, n0t

withstanding the signal conditions may change, and such signal conditions must change from danger to caution or clear,

I i v otherw se the vehicle 1 Wlll again be brought to 'a full stop upon passing interference 30 of block A, in which event the interference 30 operates on the circuit maker 4;? as de: scribed to interrupt the circuit from battery 36 to the coil of solenoid 85, dropping the f

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