US1780416A - Track installation to control railway trains - Google Patents

Description

Nov. 4, 1930. -r CLARK, ET AL TRACK INSTALLATION TO CONTROL RAILWAY TRAINS Original Filed May 20, 1927 6 Sheets-Sheet 1 Nov. 4, 1930. T. E. CLARK ET AL 1,780,416

TRACK INSTALLATION TU'CONTROL RAILWAY TRAINS Original Filed May 30, 1927 6 Sheets-Sheet 2 INVENTORS ATTORNE Nov. 4, 1930, T; E, CLARK ET AL 1,780,416

TRACK INSTALLATION TO CONTROL RAILWAY- TRAINS Original Filed May 20, 1927 6 SheetsSheet 3 ATTORNEY NOV. 4, 1930. I E, CLARK ET AL 1,780,416

TRACK INSTALLATION TOCONTROL RAILWAY TRAINS Original Filed May 20, 1927 6 Sheets-Sheet 4 m INVENTOR iififlgi ATTORNEY Nov'. 4, 1930. T. E. CLARK ET TRACK INSTALLATION TO CONTROL RAILWAY IRAINS Original Filed May 20; 1927 ATTORNEY Nov. 4, 1930. T. E. CLARK E 1,780,416

TRACK INSTALLATION TO CONTROL RAILWAY TRAINS Original Filed May 2 0, 1927 6 Sheets-Sheet 6 mwa mwfiw ATTORNEY Patented Nov. 4, 1930 UNITED STATES PATENT OFFICE THOMAS E. CLARK AND JAMES E. CLARK, OF DETROIT, MICHIGAN, ASSIGNORS T CON- TINUOUS TRAIN CONTROL CORPORATION, OF DETROIT, MICHIGAN, A CORPORATION 01 MICHIGAN TRACK INSTALLATION T0 CONTROL RAILWAY TRAINS Substitute for abandoned application Serial No. 192,839, filed May 20, 1927. This application filed December 12,1929.

This invention relates to control systems for railway trains traveling tracks divided into blocks whereby one or both of two radio-frequency currents may be impressed upon the track rails at spaced stations in order that electro-magnetic force or flux may be picked up from adjacent the rails by receptors on the locomotives or other vehicles provided with automatic brake installations and controlling instrumentalities for such brakes,so that the operation of the vehicle may be governed by such radio-frequency currents, and its object is to provide transmission instrumentalities which will impress current of predetermined.

frequency upon the rails of a block when the block in advance is occupied, and which will impress a current of another and preferably higher frequency upon the rails of a block when the block in advance is unoccupied, and which will impress both of said currents upon the rails of the last block of controlled track so that said instrumentalities on the locomotive will respond thereto and render the automatic brake mechanism inoperative while the vehicle passes over the rails of noncontrolled territory, such trackway installations being so constructed that no current is ii'npressed upon the rails of any block unless such block is occupied.

A further object of this invention is to divide each block of controlled track of sufficient length into cut-sections and to impress such current on only such sections as are occupied and to so adjust the transmission inl strumentalities that substantially the same predetermined electro-inagnetic flux will be present in each cut-section in turn, as re quired.

Another obiect of this invention is to make use of well known and largely-used railway signal systems to assist in the control of the train control instrumentalities.

The present application is a substitute for abandoned application, Serial No. 192,839, filed May 20, 1927.

In the accompanying drawings Fig. i is a diagrammatic view of a track installation and three auxiliary current trans initting instrumentalities connected thereto,

Serial No. 413,689.

the mainniechanism being operatively'positioned for clear track conditions.

Fig. 2is a view similar to Fig. 1 with fewer axillary instrumentalities, the parts being positioned fordangefitrack conditions, but non-operatin Fig. 3 is a view of the instrumentalities shown in Fig. 2, but operating.

Fig. 4 is a similar view of a track-side station not equipped with auxiliary instrumentalities.

Fig. 5 is a view similar to Fig. 3, but operating under a dilferent track condition.

. Fig. 6 is a diagrammatic View of a station adapted to transmit two radio-frequency currents of different wave lengths simultaneously.

Figs. 7 and 8 are views illustrating the connections betweenthe semaphore and the control installations.

The rails in Figs. -1, 2, 3, and 5 of the the drawings are shown divided into cut-sections of blocks by insulations 1, preferably at points about one-half mile or 800 meters apart, although these distances may be varied greatly, and at the ends of these blocks: the signal posts '10 are shown conventionally. A. control station is located at the exit end of each block andthe direction of traffic is supposed to be from left to right. WVhen a block is occupied, no effective current passesfrom the control ins runientalities at the exit end thereof along the rails toward the entrance end beyond the vehicle occupying the block, and another vehicle entering in such block at its entrance end will not be affected by current in the rails of two cut-sections 23 and 45 separated by insulators 1. The trackway installations are energized by current taken from the wires 8 and 9 which carry A. 0. current of preferably 110 volts. The several installations and the blocks controlled thereby are designated by the capital letters A and O to F inclusive, and the blocks controlled by stations A, D and F are shown occupied by vehicle T, while adjoining ends of the blocks controlled by stations E and F are shown occupied by train TT. The signal post 10 at the end of each block is connected to a switch 11 which controls one of the circuits connected to the adjacent signal battery 18. Switch 11 is so constructed that it will-be opened by the semaphore signal at danger, that is, when the block is occupied at whose entrance end it is located, but this switch will be closed when that block is unoccupied. While the occupancy of the next block in advance is indicated by the signal, it has no effect on the switch, which remains closed when the signal indicates caution or clear. Neither the signal nor the switch and the circuit controlled thereby need be considered as they form no part of the present invention, being merely shown to indicate that the present system will not interfere with these parts of a signal system.

The relays 14, 15, 16 and 17 of the signal system are made use of, together with the battery 18. The several armatures of the relays are indicated by the small letters a and b and in the specification will be designated thereby together with the numeral pertaining to the relay. WVhile we speak of a plurality of armatures for relay 14 and others, these are in fact merely independent contacts on the same armature, but the separate lettering is more convenient.

The relay 14 connects to the rails at the exit end of the controlled block by means of wires 18 and 19 and is normally energized by the track battery 20 connected to the entrance end of the last cut-section of that block. Relay 17 at any station connects to the entrance end of the next block in advance by wires 21 and 22 and is normally energized by track battery 85 connected to the exit end of the first cut-section of that block.

The mechanism for impressing radio-frequency current upon the rails so as to create electromagnetic flux along the rails receives :5 its operative current from the line wires 8 and 9, the wire 27 adj ustably connecting the wire 9 to the primary winding 36 of the main transformer 28, and the wire 29, armature 30 and wire 31 connecting this primary winding to the line wire 8 when relay 30 is energized and wire 47, and back over wires 48. Thecurrent for the filament of tube 41 travels the winding 42, wire 49 and back overwire 50.

The plate current of tube 41 travels from the filament of this tube to the plate and thence over wire 52 to the top of winding 43, while the plate current of tube travels from the filament of that tube to the plate and thence over wire 53 to the winding 43. Choke coils 54 are inserted in these wires 52 and 53 to block the radio-frequency oscillations and force them through the condensers 55 and 56 to be explained later on.

The oscillatory, circuit which generates the traincontrol currents is governed by an inductance 57 and condensers 58 and 59, from between which the wire 60 extends to wire 67 and this wire 67 extends to the connector 45. A grid leak 61 connects to wires 67 and 63, wire 63 terminating in the grid of the tube 41 and connecting to one end of the inductance 57 and to the condenser 58. The other end of the inductance 57 and the condenser 59 connect to the wire 64 which extends between the condenser 55 and a grid condenser 65 and thence to the grid of tube 40. It will thus be seen that the grid and plate of tube 41 are connected to the ends of the inductance 57 and condensers 58 and 59 whereby the tube 41 is caused to produce oscillations of a predetermined frequency, this being governed by the inductance 57 and the capacity of the condensers 58 and 59.

The plate output of tube 41 being impressed upon the grid of tube 40, the oscillations of tube 40 are governed thereby, and therefore the plate output of this tube 40 is always of the same frequency as that of the tube 41, and this is unaffected by any connections or conductors which may be attached to the circuit of tube 40. The plate output of tube 40 passes through condenser 56 to primary 68 of the output transformer 69 and thence over the wire 67 terminating in connector 45. The grid of tube 40 is unloaded through a leak 70 connecting to the wires 64 and 67 and to connector 45. Practical tests have demonstrated the advisability of using a tube 40 of fifty watts rating and a tube 41 of seven and one half watts rating.

The output transformer 69 has a secondary winding 7 2 to the ends of which the wires 73 and 74 connect, while a wire 75 connects to the adjustable contact 76, adjustable condensers 7 7 being connected into the wires 73 and 75. We prefer to use the full length of the winding 72 when transmitting current to the entrance cut-sections but use the contact 76 to ing to one end of inductance 57, the armature a of relay and wire 81 connecting to a point intermediate the ends of this inductance, is employed, the closing of this circuit shortening the inductance and increasing the rate of the oscillations and shortening the wave length of the current output. The circuits for this relay 80 will be explained later on.

Two wires 83 and 84 extend between adjacent stations whenever the blocl; of the station in advance contains no more than two cut-sections, as is the case with blocks B and E inclusive. Connected to the entrance end of the firstcut-section is the relay 17 as previously pointed out, while a track battery 85 connects to the exit'end of such cut-section. Wires 86 and 87 extend from the wires 88 and 84 to carry radio-frequency current to the primary winding 88 of transformer 89, the secondary winding 90 being connected to the rails 4 and 5 by wires 91 and 92 which also carry current from battery 85, a choke coil 98 and condenser 94 being provided to protect the battery and transformer.

Now taking Figs. 2, 8 and 4, and assuming that block E is occupied by train TT (Fig. to cause signal D to indicate danger, the following conditions occur in stations B, and. D. Vehicle T on rails 4 and 5 of block D short circuits relay C and opens the circuit from battery D to relay 0. This relay C controls the circuit to relay C and it it were not for engineering reasons connected with'the signal system already in use, the feed wires of relay 15 of any station might be extended to relay 80 of that station. The normal circuit under clear conditions for relay C when relay D is energized as hereinafter explained, is from battery D over wires 96 and 97, armature 16 wires 98, 84, and C. relay C wire 100, armature 17. wire 101, wires 83 and D armature 14, wire 103, relay 104, wire 105, armature 16, and wire 106 to battery D \Vires 83 and 84 extend onlybetween adjacent stations. The circuit for C has been traced under the assumption that C" as well as D is energized. The normal circuit of relay D is open, but when closed by armature 15 is from battery D over wire 96, 107 and 108, relay 80, wire 109, armature 15, wire 110, dropped armature 104 and wire 106 to the battery. This circuit would be closed it blocks E and F were-unoccupied, block D being occupied as shown. in the drawing.

The relay 104 of each block is inseries with relay 15 of the next station in the rear and the circuit for both is controlled by the track relay 17 of such rear station. As the circuit of each relay 1'? is opened whenever the rails of the section to which it is connected, are occupied or broken, or when any of the circuit wires of this relay 17 are broken, it is evident that relays 104 and 15 at two consecutive stations will be tie -energized whenever relay 17 between them on the present drawing) is de-energized. So long as any relay 104 is energized, relays 30, 80, 114 and 115 of the same station are deenergized and such station is non-operating as will presently appear.

When relay 15 of any station is de-energized, relay 80 or that station is also deenergized and should the block to which such station is attached be occupied, caution current will be transmitted to the rails of that block as will be explained later on.

The energizing circuit of relay 104 of block C is from battery C over wires 96 and 97 dropped armature 16, wire 105, relay 104, wire 103, raised armature 14*, wires 102, 83, B armature B wire 100, relay B wires 99, 84, C dropped armature C and back to the battery. So long as this continues, station C is non-operative, since relay 30 remains tie-energized. Should relay B be short-circuited because the entrance section of block C is occupied, or relay C be shortcircuited because the second section of block 0 is occupied, then this circuit to relay C is opened. \Vhen neither of these sections is occupied and with block D unoccupied, re-

lays C, C and B will be energized, relay C because switch 11 is closed, as will be explained later on in connection with Figs. 7 and 8. In this case the current will flow from battery C over wires 96 and 97, armature 16", wires 98, 84, B relay B wire 100, armature 17", wires 101, 83, and C a1- mature C wire 103, relay C wire 105, raised armature 16 and wire 106 back to the battery.

Relay 1) is receiving current because the first cut-section of block D is occupied and relay 17 and relay 104 of station D are de-energized because block E is also occupied. The circuit for this relay D is from battery D over wires 96 and 107 to this relay and over wire 112, dropped armature 104 and wire 106 to; the battery. lVhen relay 30 and the electron tubes are energized, the flow ofra- Clio-frequency to the rails depends upon the two relays 114 and 115. As the first cut-section of block D is occupied, relay C is deenergized and for that reason relay D is de-energized as above described. Relay D receives battery current from the battery D over wires 96, 107 and 116 and back over wire 117, armature 14, wires 118 and 112, dropped armature. 104 and wire 106 to the battery. As armature D114% is attracted, the circuit of radio-frequency current is from winding D over wire 74, armature 114 wire 120, wires 98, 84 and 87, primary winding 88 of transformer 89 attached to the rails of block I), armature 14 and Wires 103 and 73 to the other end of winding 7 2.

Relay 80 is de-energized in Fig. 3, and current of longer wave length or caution current is impressed upon the rails of block D. The full length of winding 72 is used to impress radio-frequency current on the primary winding 88 of transformer 89, and this current is stepped down by transformer 89.

In Fig. 5, station F is in clear condition, two blocks of the track ahead being unoccupied, as is indicated by signal F Rails 2 and 3 at the exit end of block F are occupied so that relay F becomes (lo-energized through its battery 20 being short-circuited by vehicle T. Relay F opens the battery circuit to relay F and closes the battery circuit to relay 115 which is from battery F over wire 96, relay 115, wire 119, dropped armature 14", wires 118 and 112, dropped armature 104 and wire 106 to the battery. The circuit for radio-frequency current closed by armature 115 is over wire 74, armature 115, wires 121 and 18 to rail 3, vehicle '1, rail 2, wires 19 and 75 to contact 76.

Relay 80 is shown energized in Fig. 5, shortening inductance 57 to cause the genera tion of radio-frequency current of higher or clear frequency, and the circuit for this relay 80 is over wires 96, 107 and 108, relay 80, wire 109, armature 15, wire 110, armature 104 and wire 106 to the battery. Energized relay 80 attracts its armature a which is connected to inductance 57 between its ends and thereby shunts a portion of this inductance. The shortening of the transformer winding 72 by means of the contact 76 is not sufficient to vary the wave length, but is merely to tune the winding to the circuits.

As the vehicle or train connects the rails, there will not be suilicient radio-frequency current between the rear end of this vehicle or train and the entrance end of the block occupied by such rear end to affectthe instrumentalities of a following train entering such block, and such instrumentalities will therefore assume danger positions. This is the case with train TT which is entering occupied block F.

Block E is shown to be short and is not divided into cut-sections, so that the mechanism comprising battery 20 and its relay are therefore omit-ted, together with transformer 89 and its connections and relay 114 and its connections. As the entrance cut-section of block F is occupied, relays 15 and 17 of station E are de-energized. As block F is already occupied, no radio-frequency current would be present in the rails at the entrance end of block F. As the train TT extends back of the connection of the wires 91 and 92 from track battery 85, relay D is de-energized and relay E is therefore ale-energized. The armatures of relays 30 and 80 of this station E assume caution positions, relay 30 receiving battery current over wires 96 and 107, the return being over wire 121, 112, armature 104 and wire 106. Armature 30 being attracted, the tubes 40 and 41 and the transformer 69 function. Relay 115 receives battery current over wire 96 and the return is ever wires 119 and 112, armature 104 and wire 106. Radio-frequency current passes from the transformer 69 over wire 74, armature 115 and wires 121 and 92 to rail 3 and from the transformer over wires 75 and 91 to rail 2. As block F is occupied, caution or low frequency current will pass to the rails bloct: E. Relay 80 is de-energized, its battery circuit being opened by dropped armature 15.

But as stated before, the occupancy of this biocl-z prevents a sufficient amount of this current passing along the rails beyond the occupying train to be appreciated by the oncoming train. Relay E is de-energized beause relay E is short-circuited by train TT.

1 illustrates an installation adapted or a block comprising three cut-sections. ration A. is similar in all respects to stations F and is similarly controlled. As

I D and blocks B and C are unoccupied, signal A indicates clear. The entrance cut-section comprising rails 6 and 7 being occupied by vehicle T, electro-magnetic flux should be there present and it flows from secondary winding 7 2 of station A over wire 74, armature 114 wires 120, 98, 84, and 123, armature 124 wires 125, 84 and 87, primary winding 88 of transformer 89, wires 86, 83 and 126, armature 124 wires 127, 83 and 102, armature 14 and wires 103 and 73 to the winding 72. Relay 124 is energized by track battery 128 connected to rails 4 and 5. As soon as this vehicle T, Fig. 1) passes onto rails 4 and 5, this relay 124 is short-circuited and opens the circuit to transformer 89 but closes the circuit to transformer 132 from wire 127 over dropped armature 124 and wire 133 to primary windin g 134, the secondary winding 135 being connected to the rails 4 and 5 by wires 136 and 130 and by wires 137 and 129. The return from transformer 132 is by wire 138 and armature 124 to wire 123. As soon as vehicle T runs onto rails 2 and 3, relay 14 becomes de-energized, relay 114 also becomes de-energized, but relay 115 picks up its armature and radiofrequency current passes to rails 2 and 3 as before described.

it the end of the controlled territory the installation shown in Fig. 6 is located for the purpose of transmitting radio-frequency currents of both wave lengths above spoken of upon therails of the track simultaneously so that the automatic control instrumentallties on the locomotive will be locked in nonbraking position where they remain until controlled territory is again entered. This installation is controlled by the presence of a vehicle T on the rails 2 and 3 to which are connected the wires and 141 which lead from the battery 142, which normally energizes relay 17 of the next station in the rear. As soon as said relay 17 is short-circuited, the circuit from the battery in Fig. 6 to relay 15 of the next station in the rear is opened, which circuit is from said battery 13 of the station shown in Fig. 6 over wires 142 and 143, armature 144", wires 1 5 and 84, wire 99 of the next station in the rear, relay 15, wire 100, armature 17 wires 101 and 83 to the station shown in Fig. 6, wire 146, relay 147, wire 148, armature 144 and wire 149 to the battery. But this circuit is open so relay 147 is deenergized, closing circuits to both relays 30 and. both relays 150 shown in Fig. 6, as follows. From the battery 13 shown in Fig. 6, wire 142 connects to relay 150 on the right while a branch 152 connects to adjacent relay 30. W ire 153 connects this relay 30 to wire 154 extending to armature 147 and this connects to the battery by wire 149. For the installation on the left, wire 155 connects the battery to relay 150, while the branch 156 connects to adjacent relay 30 which is connected to armature 147 by wire 157 from which the branch 158 connects to relay 150. Armature 147 is connect-ed to the battery by wire 149.

The radio-frequency currents are conducted to rail 2 by wire 74, armature 150, wires 160, 161, and 141, and to rail 3 by wires 75, 162 and 140. The relays shown and designated as 16 and 144 are part of the signalling system and are there preferably slow-acting. They are herein shown as such, but quick acting relays will serve the same purpose in the present installations.

hen a train leaves uncontrolled and enters controlled territory, the mechanism 'shown at the left in Fig. l-may be used to inform the engineer by means of lamps R and G of the condition of the control mecha- 1 nism. The relay 165 shown here is a part of the signal system and may be disregarded. The track battery 85 connects to the rails 6 and 7 and normally energizes the relay 166 which attracts its armatures a and b sothat a circuit from the line wires 8 and 9 to trans- 127, 83 and 102, armature 14, wire 103, relay A wire 105, armature 16 and wire 106 to the battery. When relay 104 becomes deenergized by its circuit being opened by relay 166 being de-energized, while relay 14 is still energized, radio-frequency current passes out on wires 83 and 84 as before described. This current passes in part to transformer 89 so that the vehicle T may pick up its control current. But part passes over wires 168 and 169 to the primary winding 170 of transformer 167, whose secondary winding 171 is connected to the grid of tube 172. The grid leak 173 of this tube connects to the winding 171 by wires 174, 175 and 176. The filament of this tube is heated by current from the battery 177 passing over wire 178 to the filament and the return being over wires 179' and 180, dropped armature 166 and wire 182. When this grid is energized, plate current passes fom line wire 8 over wire 183, relay 184, and wire to the plate and from the filament over wires 178 and 186 to wire 9. Energized relay 184 closes the circuit from battery 177 over wire 182, dropped armature 166 wire 180, armature 184 wire 187, safe lamp G which is preferably green, and wires 188 and 175 to the battery. But if no radiofrequency current is present in wires 83* and 84 relay 184 will not be energized and this battery current will flow from dropped armature 184" over wire 190 to danger lamp R, which is preferably red.

If lamp G receives current and the signals on thevehicle show either clear or caution conditions in the track ahead, or if lamp R is receiving current andthe signals on the vehicle indicate danger, the engineer knows that both track and vehicle instrumentalities are functioning properly. If either lamp is receiving current and the signals on the vehicle do not function properly to correspond, the engineer knows that the vehicle instrumentalities are out of order. If neither lamp shows current, he knows that the track installation next ahead is out of order. In an one of these cases, he is properly forewarne Referring now to Figs. 7 and 8, which diagrammatically illustrate a signal installation of well known construction, the relays 15, 16 and 17 are positioned substantially as shown in Figs. 1 to 6 inclusive. Relay 15 is shown equipped with additional armatures b and c to control the signal or semaphore arm 204 which is mounted on a shaft 203, the danger position when the block at whose entrance end it is positioned is occupied, being vertical or clear when that block and the next in advance are unoccupied, and being in intermediate position to indicate caution when the next block in advance is occupied. This shaft 203 is rotated by means of a motor 205 and gears 206. i

The relay 15 is shown in Figs. 1 to 6 inclusive as a neutral relay, but when used in consemaphore being in horizontal or nection with a signal installation it is a polarneutral relay, having a polar armature 0. hen block D is occupied, no current passes over wires 99 and 101 to relay C, as before described, and armatures C and C drop because relays C and C are de-energized. No current passes to motor 205. Relay E is energized when block F is unoccupied, for the reasons to be explained later on. vVhen relay E is energized, positive current flows from battery E over wires 96 and 97, armature 16", wires 98, 84 and 99 relay 15, wire 100, armature 17 wires 101, 83 and E relay 104, wire 105, armature 16 and wire 106 to the battery. This causes armature D to swing clock-wise, the other armatures of this relay being attracted. But if relay E were de-ener ized, current from battery E would flow over wires 96 and 97, armature 16% wire 105 and the circuit just named reversed, causing armature 0 of relay D to swing counterclock-wise.

On the shaft 203 (Fig. 8) are three conductors in the form of plates 193, 194 and 195, insulated from each other and from the shaft. Vhen the parts are as shown in Figs. '4' and 3, which occurs when relay 15 is de-energized because of the block in advance being occupied, no current passes to this signal installation. hen negative current passes to relav 15 because of relay 16 of the next block in advance being tie-energized, current will fiow from battery 13 (Fig. 7) over wires 96, 97 and 200, motor 205, wire 197, plate 193, wire 196, armature 15 and wire 106 to the battery. Motor 205 will turn its shaft about forty-five degrees and thus move plate 193 to break the circuit over wire 196. Other mechanism is provided to lock the motor but that is well known and need not be described. Semaphore now holds its intermediate caution position. At the same time, plate 194 connects wires 192 and 191 so that current will flow over wire 192, plate 194, wire 191, relay 16 and wire 201, energizing this relay which thereupon attracts its armatures and causes positive current to flow to the next station in the rear to relay 15 of that station. That relay swings its armature c clock-wise so that as soon as motor 205 of that station has turned forty-five degrees, plate 195 on shaft 203 will connect wires 193 and 199 so that current will flow from the battery to the motor as before and then over the wires 197, 199, plate 195, wire 193, armature 15 and wire 106. The motor will thereupon turn through additional forty-five degrees and until semaphore 204 is vertical.

The direction of current from each battery 13 to relay 15 of the next station in the rear therefore controls the position of the semaphore of that next station and current in either direction results in relay 16 being energized and relay 15 of the next station in the rear being positive energized.

The signal installation may therefore be said to be one block ahead of the control in stallation in indications, for the semaphore arm 204 at the entrance end of a block indicates the character of radio-frequency current which would be impressed upon the rails at the exit end of that block should that block be occupied, excepting that when the semaphore is horizontal, no such current is impressed upon the rails.

The wires 83 and 84 therefore not only con duct the signal current which is the control current for this control system but also the radio-frequency current to the entrance cutsections of the several blocks which are of sufiicient length to warrant cut-sections. The signal batteries 13 and the track batteries of the signal system are thus made use of in this control system together with the line wires 83 and 34 and the poles supporting them.

WVe claim 1. In a track installation to control railway trains, the combination of a trackway divided into blocks each comprising a plurality of cut-sections, a current source and a track relay connected to each cut-section, a radio-frequency current generator for each block and comprising an output transformer embodying a secondary coil, connections between said secondary coil and the rails of the several cut-sections, a relay for each cutsection to close said connections thereto, a current source, and circuits between said current source and said last named relays which are closed when said track relays are deenergized.

2. In a train control system, the combination of a trackway divided into blocks, each comprising a plurality of cut-sections, a radio-frequency current generator at the exit end of one block embodying an output winding for said block, normally open circuits connecting said output winding to the exit end of the rails of each section, a track battery connected to one end and a track relay connected to the opposite end of each track section, a control relay having an armature adapted to cause the closing of the supply circuit for said generator, a current source, a circuit between said current source and said control relay which circuit is controlled by said track relays. and a relay for the circuit to each cut-section adapted to close the same when the track relay thereof is de-energized.

3. In a train control system, the combination of a trackway divided into blocks, each comprising a plurality of sections, a radiofrequeney current generator and embodying output windings normally disconnected from the exit ends of the several block sections, a control relay adapted to normally hold open the supply circuit for said generator, a current source for said relay, a track battery connected to one end and a track relay connected to the opposite end of each track section, and a circuit between said current source and said control relay adapted to be opened when either of said track relays is short-circuited, and means controlled by said track relays to close the circuit between said output winding and each section as the track relay thereof becomes short-circuited.

4;. In a train control system comprising track rails divided into blocks and the blocks divided into sections, a generator for radiofrequency currents embodying an output transformer including output windings, normally open circuits connecting said windings to the rails of each block-section, and means controlled by the occupancy of each section to cause the closing in turn of said circuits between the output windings and said blocksections as such block-sections are consecutively occupied.

5. A train control system comprising track rails divided into blocks and the blocks divided into sections, a generator for radiofrequency currents embodying an output transformer including output windings, and circuits connecting said windings to the rails of each block-section and means whereby the occupancy of each bl0ck-section in turn causes the passage of radio-frequency current to that section.

6. A train control system comprising track rails divided into blocks and the blocks divided into sections, a generator for control current for each block section and independent output windings for the several sections of each block deriving energy from said generator, and circuits connecting said windings to the rails of each block-section and means whereby the occupancy of each block-section in turn causes the passage of control current to that section.

7. A train control system comprising track rails divided into blocks and the blocks 1 divided into sections, a generator for radiofrequency currents embodying an cutput transformer including output windings, and wires connecting said windings to the rails of each block-section and means whereby the occupancy of one section of the block causes the transmission of radio-frequency current to the rails of said section without affecting the other section of said block.

8. A train control system comprising rails divided into blocks and the blocks divided into sections, means for impressing radiofrequency currents of two different frequencies upon the rails of one of the blocks, said means embodying an out-put transformer, output windings, wires connecting said windings to the rails of each block-section, means responding to the occupancy of the block next in advance to predetermine the frequency of such currents, and means responding to the occupancy of a section to cause the impression of radio-frequency current on that section without affecting the other section of the block.

9. A train control system comprising track rails divided into blocks and the blocks divided into sections, a source of alternating current, means at each block for transforming said current into radio-frequency currents, normally inoperative means connected to each block-section toconvey such currents to such block sections independently of each other, means responsive to the presence or absence of trains in the block ahead to determine the frequency of the currents thus impressed, and means responsive to the occupancy of each section to select the means connecting the current transforming means to carry such radiofrequency current to the occupied blocksections.

10. A train control system adapted to be installed in connection with the signal system for a track divided into blocks and which embodies track batteries and relays which generate and control signalling current, three-position semaphores and batteries for supplying current therefor, a generator for radio-frequency currents adapted to impress currents of different wave lengths upon the rails, and means controlled by the signalling current derived from said track batteries to select the wave length to correspond to the concntions indicated by the semaphore.

11. A train control system adapted to be installed in connection with the signal system for a track divided into blocks and the blocks divided into cut-sections, which system embodies track batteries and relays, three-position semaphores and batteries for supplying current therefor, and line wires between adj acent semaphores to carry the current for controlling said semaphores, a generator for radio-frequency currents adapted to impress currents of different wave lengths upon the rails at exit end of each cut-section, means controlled by the current controlling the semaphores to select the wave lengths to correspond to the conditions indicated by the semaphores, and conductors from said generators to said line wires and from said line wires to the cut-sections remote from said generators to conduct radio-frequency currents thereto.

THOMAS E. CLARK. JAMES E. CLARK.

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