US2337173A - Remote control apparatus - Google Patents

Description

G. W. BAUGHMAN REMOTE CONTROL APPARATUS v Dec. 21, 1943.

Filed May 14, 1941 gw w lNV ENTOR Gear e Baqghman M. IIIS ATTORNEY man Patented Dec. 21, 1943 UNITED STATES A'l'EN'l' OFFICE The Union Switch & Si

vale, Pa.,

gnal Company, Swissa corporation of Pennsylvania Application May 14, 1941, Serial No. 393,363

9 Claims.

My invention relates to remote control apparatus and particularly to improved means for providing a plurality of distinctive indications in each direction over a single line circuit.

The means provided by this invention is particularly adapted for use in a railway signaling system to control the signals for two directions of trafiic. However, the invention is not restricted to use in this manner and it is contemplated that the system may be employed in other situations.

It is an object of my invention to provide an improved system having a single line circuit and having means for concurrently supplying energy at opposite ends of the line circuit.

A further object of my invention is to provide an improved system of the type described in which the means for supplying energy to the ends of the line circuit are independent of each other so that cutting off of the supply of energy by the means at one end of the line circuit does not affeet the supply of energy by the means at the other end of the line circuit.

Another object of my invention is to provide system of the type described and incorporating improved means to prevent false operation of the equipment when the line circuit is interrupted.

A further object of my invention is to provide an. improved signaling system.

Other objects of my invention and features of novelty will be apparent from the following description taken in connection with the accompanying drawing.

I shall described one form of improved signaling system embodying my invention, and shall then point out the novel features thereof in claims.

In the drawing, the single figure thereof is a diagram showing a stretch of railroad track equipped with signaling apparatus embodying my invention.

Referring to the drawing, there is shown therein a stretch of single track railroad over which traffic moves both directions. To facilitate description of the apparatus it will be assumed that the right-hand end of the diagram is east the left-hand end is west. Accordingly, train movements from left to right are eastbound, while train movements from right to left are westbound.

The rails of the track stretch are divided by insulated joints into successive track sections designated ll, 2T, etc. Each of these track sections is provided with a suitable track circuit comprising a track battery located at one end of the track section and a track relay, designated TR with an appropriate prefix, located at the other end of the track section.

The track stretch includes at the west end thereof a passing siding which is connected with the main track by means of a switch W.

Movement of eastbound trains through the track stretch is governed by signal 23, which governs movement of trains beyond the passing siding, and by intermediate signal 45'. Movement of westbound trains through the track stretch is governed by signals is and The system provided by this invention is directed to means to control signals 2S and 3S.

The signals IS and is may be controlled by trafiic conditions in advance thereof in any suitable manner well known in the art. In situations where there is but one intermediate signal between passing sidings for each direction of traffic the signal is and the headblock signal located at the leaving end of the adjacent passing siding in advance and controlling westbound traffic may be controlled by apparatus identical with that provided to control signals 28 and 38.

The equipment for controlling the signals 28 and 3S includes line wires 23 and 2| which provide a line circuit extending between signals 23 and 35. At one end of this line circuit are located line relays 2? and 2N which govern the signal 28, while line relays 33? and 3N are located at the other end of the line circuit and control the signal 38. In addition, code transmitters lECT and ISECT are located at opposite ends of the line circuit and control the sup-ply of energy to the line circuit and also control connection of the associated line relays with the line circuit.

The line relays P are polarized relays having contacts which are moved to one position when energy of one polarity is supplied to the relay windings and to another position when energy of the other polarity is supplied to the relay windings. In addition, these relays are of the type the contacts of which when moved to either position remain in that position when the relay winding is deenergized.

The line relays N are of the polar biased type and have contacts which are released when the relay winding is deenereized and become picked up only when energy flows in one direction through the relay winding.

The relays P control connection of the assoelated relays N with the line circuit so that if the contacts of the relays P respond to a change in the polarity of the energy supplied to the line circuit, they change connection from the line wires to the relays N so that energy flows in the windings of the relays N in the direction to pick up the relay contacts. This arrangement of the line relays P and N is not a part of this invention, but is shown in Letters Patent of the United States No. 2,203.888 of Harry E. Ashworth, granted June 11, 1940.

The code transmitters TECT and IBcCT employed at the opposite ends of the line circuit have contacts which are continuously actuated between their picked-up and released positions. These devices are selected so that their contacts have substantially different rates of operation. Thus the contacts of the device IBtCT are moved to their picke-up positions 180 times a minute, while the picked-up periods of the contacts are separated by periods of equal length during which the contacts occupy their released position. Similarly, the contacts of the device 750T have '75 picked-up and released periods each minute. As these devices operate at substantially different speeds, these contacts do not operate in synchronism and there are frequently recurring periods during which the contacts of one of the devices are picked up and the contacts of the other of the devices are released.

Each signal location is provided with a suitable source of direct current, such as a storage battery, not shown, the terminals of which are designated B and C.

The equipment is shown in the condition which it assumes when the track stretch is vacant. At this time the track relays are all picked up so that the line circuit is complete. In addition, at this time relay III and relay ll-I are picked up. The relay lI-I is controlled by trafiic conditions in sections IT and ET, while relay 4H is governed by trafiic conditions in advance of signal 48. The relay 4H may be controlled in a manner similar to 31-1 so that it is picked up when and only when the track stretch between signal 45 and the adjacent passing siding in advance is vacant. The relay 4H may also be employed to control the signal 48 so that this signal displays a stop indication when this relay is released and displays a proceed indication when the relay is picked up. Likewise, the relay lI-I may be employed to control the signal IS so that tru's signal displays a red or stop indication when the relay is released and a proceed indication when the relay is picked up.

During the picked-up periods of the contacts of code transmitter lEiCT connection is established to supply energy to the left-hand or west end of the line circuit. At this time terminal 13 of the source is connected through resistor 2 1, front contact 25 of relay IH, front contact 26 of code transmitter 750T, front contact 2'! of track relay 2TB, and front contact 28 of track relay 3TH to line wire 28, while terminal C is connected through front contact 3! of relay IH, front contact 32 of code transmitter 150T, front contact 33 of relay 2TB, and front contact 34 of track relay 3TB.

During the reelased periods of code transmitter lSllCT connection is established to supply energy from the line circuit to line relays BP and 3N. At such times line Wire 2 is connected through front contact 38 of track relay HTR, front contact 39 of track relay 5TB, and back contact 40 of code transmitter lStCT to one terminal of the windings of relays 3P and 3N, while line wire 2| is connected through front contact 43 of track relay 4TB, front contact 44 of track relay 5TB, and back contact 45 of code transmitter IG JCT to the other terminal of the Wind: ings of relays SP and 3N.

Accordingly, during the periods in which the contacts of code transmitter 750T are icked up and the contacts of code transmitter itfiCT are released energy is supplied over the line circuit to the relays SP and 3N. As the contacts of relay IH are picked up, this energy is of normal polarity and causes the contacts of relay 33? to be moved to their left-hand or normal position as shown so that energy from the line circuit flows in the proper direction in the winding of relay 3N to pick up the contacts of this Winding.

Similarly, when the contacts of code transmitter iStCT are picked up, connections are established to supply energy to the right-hand or east end of the line circuit. At such times ter minal B of the source is connected through resistor front contacts 5! of relay AH, front contact of code transmitter 306T, front contact 39 of track relay 5TB, and front contact 353 of track relay 4TB to line wire 2%, while terminal C is connected through front contact 52 of relay AH, front contact if; of code transmitter 3501, front contact is of track relay 5TB, and front contact as of track relay 4TB to line wire 2 1.

During the released periods of code transmitter EECT connection is established from the line wires to the windings of relays El and 2N. At such times line wire 23 is connected through front contact 28 of track relay 3TB, front contact iii of track relay 2TB, and back contact 23 of code transmitter 75C? to one terminal of the relay windings, while wire 25 connected through front contact 3d of track relay STR, front contact 33 of track relay HR, and back contact 32 of code transmitter 'ffiCT to line relays EP and 2N.

Accordingly, during the periods in which the contacts of code transmitter i83CT are picked up and the contacts of the code transmitter are released energy is supplied over the line circuit to the line relays 2? and 2 As the contacts of relay EH are picked up, the energy supplied over the line circuit is of normal pclarity so that the contacts of relay occupy their left-hand or normal position as shown and establish connection from the line circuit to relay ZN so that energy flows in the winding of relay 2N in the direction effective to pick up the contacts of this relay.

From the foregoing, it will be seen that when the track stretch is vacant, impulses of energy are supplied from each end of th line circuit to the line relays at the other end of the line circuit. These impulses occur when the contacts of the code transmitter at the supply end of the circuit are picked up and the contacts of the code transmitter at the other end of the line circuit are released. As the code transmitters operate at different rates, this relationship between the contacts of these devices recurs at frequent in tervals so that impulses varying in length are supplied to the line relays at each end of the line circuit at frequent intervals.

On the supply of energy to the line relays at one end of the circuit the contacts of the relay N pick up, while on interruption of the supply of energy the contacts of the relay release. As a result of this movement of the relay contacts, the two portions of the primary winding of the decoding transformer D1 are alternately energized so that impulses of energy are induced in the transformer secondary winding, while a contact of the line relay rectifies the energy supplied from the transformer secondary winding to the associated relay H. The relays H are of a type the contacts of which are low in releasing so that they will remain picked up during the intervals between the supply of impulses of en ergy thereto.

It has been found that when code transmitters of substantially different frequency are employed at opposite ends of the line circuit, energy impulses of adequate length are supplied to the line relays at each end of the line circuit to cause enough energy to be supplied through the decoding transformers DT to the relays H to maintain these relays picked up.

It has also been found that these energy impulses occur at sufficiently frequent intervals that the release periods of the relays H need not be excessively long to bridge over the intervals be tween the supply of energy impulses to these relays. Accordingly, as long as the track stretch is vacant, energy of normal polarity is supplied over the line circuit to the line relays and the relays N follow the code so that the associated relays H are picked up. As the energy is of nor- Inal polarity, the contacts of the line relays P occupy their normal or left-hand. positions as shown. At this time the circuit of the green or clear lamp G of signal 28 is establish d and includes front contact 55 of relay 2H and n rrnal polar contact 55 of relay 2P, while the circuit of the green or clear lamp G of signal 58 is also established and includes front contact 51 of relay 3H and normal polar contact of relay 3P.

Operation of equipment on passage of eastbound train through the track stretch When an eastbound train enters section ET, track relay ETR releases and interrupts the circuit of relay lI-I so that the contacts of this relay release and cut off the supply of energy to the west end of the line circuit. Accordingly, energy is no longer supplied to relay 3N and the contacts of this relay rernain released so that energy is not supplied through the decoding transformer 313T to relay 3H and its contact 5? releases and interrupts the circuit of the green lamp G of signal 38 and establishes the circuit of the red or stop lamp R of this signal.

At this time energy continues to be supplied over the line circuit to the relays EP and 2N so that signal 28 continues to. display green or clear indication.

When the train advances into section 2T, track. relay 2TB releases and its contacts 2? and 33 interrupt connection oetween the line wires and the contacts and 32 or" cod transmitter 'i5CT and establish connection from the line Wires directly to the line relays 2? and 2N. This addi tionally prevents supply of energy to the line circuit during the picked-up periods of the contac s of code transmitter HGT and thereby insures that signal 33 will display its red or stop indication. In addition, as the line relay BF and 2N are connected directly to the line wires instead of being connected thereto through the heel; contacts of code transmitter the line relays receive energy whenever the contacts of code transmitter @8881 are picked Accordingly, at this time there is an increase in the frequency and the duration of the energy impulses supplied to the line relays Z? and 2N so that these relays operate more positively to maintain the display of a clear indication by the signal 28.

In addition, as the line relays 2F and 2N are the pick-up circuit of relay 48R.

directly connected to the line wires 25} and 2| when the contacts 2'! and 33 of track relay 2TB are released, instead of being connected thereto through the contacts 26 and 32 of the code transmitter lEC'I, if the line wires 28 and ti become crossed with'other wires so that steady energy is improperly supplied thereto the relay 2N will be steadily picked up and energy will not be supplied through the deccding transformer 213T to the relay 2H. Accordingly when a train is present in section 2T the signal 23 will provide its red or stop indication if steady energy is improperly supplied to the line circuit.

When the train advances into section 3T, the contacts of track relay 3TB release and interrupt the line circuit to thereby prevent supply of energy to the line relays at either end of the circuit. Accordingly, relay ZN ceases to follow code and energy is no longer supplied through the transformer EDT to the relay 2H and contact 55 releases and establishes the circuit of the red or stop lamp of signal 28.

In addition, on release of relay 3TH contact 28 short circuits the portion of the line circuit connected to line relays SP and 2N, while contact 34 short circuits the other portion of the line circuit. As the two portions of the line circuit are short circuited, there is no possibility that the line relays will be energized it connecti n is improperly established from a source of current to either portion of the line circuit.

At this time energy continues to be supplied to the east end of the line circuit during the picked-up periods of code transmitter actor, but the resistance 5% limits the value of these energy impulses and prevents excessive drain on the battery or other source or" supply. Similarly, when the train advances far enough to vacate sections 5T and ET, energy is supplied to the west end of the line circuit during the picked-up periods of the contacts of the code transmitter 750T, but the resistance E 3 limits the value of these impulses and prevents excessive drain on the battery.

When the train advances into section 4T, track relay 4TH releases and additionally interrupts the line circuit and also short circuits the two portions of the line circuit as explained in connection with track relay 3TH.

When the train advances into section 5T, track relay 5TB releases and additionally interrupts the line circuit, while its contact lid establishes In addition. when relay 5TB releases, it deenergizcs relay 6H by means not shown. However, because of the slow release characteristic of this rela its contact 6! remains picked up after release of the contacts of relay 5TB, so that the picloup circuit of relay 3333 is established. On picking up of the contacts of relay GER its contact 32 establishes a stick ci cuit t maintain the reie energized as long as track relay or relay 4H released.

In addition, when track relay is its contacts 39 and 44 connect the line relrand 3N directly to the lid wires 25 and 2! that relay 3N will be steadily energized if energy is improperly supplied to the line wires, as ex plained above in connection with relays 2P and 2N.

When the train advances far enough to vacate section 4T, the track relays or" the various sections pick up and establish the line circuit so that energy supplied to the west end of the line circuit during the pick-up periods of the contacts of code transmitter 1501" feeds to the line relays 3? and 3N over connections which include back contacts 39 and Ml of track relay TB. As relay H1 is picked up, the en rgy supplied to the line circuit is of normal polarity so that the line relay 3? and relay 31-1 cooperate to establish the circuit of the green or clear lamp G of signal 38.

As long as section ET is occupied, energy is not supplied to the east end of the line circuit and signal 28 continues to display its red or stop indication. When section 5T is vacated, contacts 39 and M of relay 5TB pick up and establish connections so that energy of reverse polarity is supplied to the line circuit during the picked-up periods of the contacts of the code transmitter 5139GT. At these times terminal C is connected through front contact M of relay 4S3, back contact 5! of relay lH, front contact 49 of code transmitter iiiilCT, front contact 39 of relay 5TB, and front contact 33 Of rela dTR to line wire 20, while terminal B is connected through resistance Eiil, front contact iii: of relay llSR, back contact 52 of relay iH, front contact 55 of code transmitter front contact M- of track relay 5TB, and front contact it of track relay 5TB, to line wire 2 l.

The energy supplied to the east end of the line circuit feeds to the line relays BF and 2N, and

as this energy is of reverse polarity, it causes the contacts of relay 2P to shift to their right-hand or reverse positions. Accordingly, when contact 55 of relay 2H picks up, it establishes a circuit including reverse polar contact 56 of relay 2? to light the yellow or caution lamp Y of signal 25.

When the train vacates section ET and track relay 5TB picks up, contact [iii interrupts one circuit of relay iSR, but this relay continues to be energized by current supplied over back contact 65 of relay Ail-l".

When the train advances far enough to vacate the single track stretch between signal AS and the adjacent passing siding in advance, the relay GE is energized by means not shown. On picking up of the contacts of relay 5H its contact 6! interrupts the stick circuit for the relay ASE, while its contacts 5! and 52 interrupt the circuit for supplying energy of reverse polarity to the line circuit and establish the circuit for supplying energy or normal polarity to the line circuit. On this change in the polarity of the energy supplied to the line circuit, and to the line relay 2?, the contacts of this relay shift to their left-hand or normal position and contact 55 establishes the circuit of the green or clear lamp of signal 28.

Operation of equipment on passage of a westbound train through the track stretch When a westbound train enters the overlap section at the end of the passing siding east of signal relay 6H is deenergized by means not shown and places signal 38 at stop. On release of contacts 5! and 52 of relay filH the supply of energy to the line circuit is cut on since at this time relay 48R remains deenergized.

As the supply of ener y to the east end of the line circuit is cut off, no energy is supplied to line relays 2? and 2N so that relay 21-1 releases and establishes the circuit of the red or stop lamp R of signal 28. At this time energy of normal polarity continues to be supplied to the west end of the line circuit so that signal 33 continues to display its green or clear indication.

'When the train advances far enough to enter section 5T, track relay 5TB releases and its contacts 39 and Q4 connect the line wires 28 and 2i directly to the line relays SP and 3N so that these relays are energized whenever the contacts of code transmitter T are picked up regardless of the position of the contacts of code transmitter lBfiCT. As explained above, this makes the action of the relays more positive and makes it more certain that signal 38 will display its green or clear indication while the train is approaching the signal and is within view of the signal.

When the train enters section QT, track relay 4TB releases and both interrupts the line circuit and short circuits the two portions of the circuit. Accordingly, relay 3N ceases to follow code and relay 3H releases and lights the red or stop lamp of signal 38.

When the train enters section 3T, track relay 3TR releases and interrupts the line circuit and short circuits portions thereof, while when the train enters section 2T, track relay 2TB releases and its contact 6'! interrupts the circuit of relay ll-l and establishes the pick-up circuit of relay ISR. This circuit includes front contact 68 of relay ITR, while when relay ISR. picks up, its contact 69 establishes a holding circuit to supply energy to the relay on release of contact 68 of relay lTR. When the train enters section IT, track relay [TR releases and completes the stick circuit of relay ISR so that the contacts of this relay remain picked up as long as section IT is occupied.

When the train Vacates section 5T relay 4H is energized by means not shown and its contacts 5! and 52 are picked up so that energy of normal polarity may be supplied to the line circuit.

When the train advances far enough to vacate sections ET and GT, the track relays of these sections pick up so that energy of normal polarity is supplied to the line circuit during the pickedup periods of the contacts of the code transmitter I3BCT. When the train advances far enough to vacate section 3T, track relay 3TB picks up and energy from the line circuit is supplied over back contacts 2'! and 33 of relay 2TB to the line relays 2? and 2N. Accordingly, energy is supplied through the decoding transformer 2DT to relay 2H so that contact 55 of relay 2H picks up and establishes the circuit including normal polar contact 56 of relay 2? to light the green or clear lamp of signal 2S.

When the train advances far enough to vacate section 2T, track relay 2TB picks up and establishes connections to supply energy of reverse polarity to the line circuit during the picked-up periods of the contacts of code transmitter lECT and to permit energy to be supplied to the line relays 2P and 2N during the released periods of the contacts of code transmitter 'lECT. At this time terminal B is connected through resistance Z i, front contact 12 of relay ESR, back contact 31 of relay iH, front contact 32 of code transmitter 150T, front contact 33 of track relay 2TR, and front contact 34 of track relay 3TB, to line wire 2!, while terminal C is connected through front contact '53 of relay ESE, back contact 25 of relay ill, front contact 26 of code transmitter leCT, front contact 2! of track relay 2TB, and front contact 28 of track relay 3TB to line wire 28.

The energy supplied to the west end of the line circuit is supplied to the line relays 3E and 3N during the released periods of the contacts of the code transmitter IEUCT. As the energy is of reverse polarity, the contacts of relay 3? shift to their reverse or right-hand positions so that on picking up of contact '51 of relay 3H a circuit including reverse polar contact 58 of relay 3P is established to light the yellow or caution lamp Y of signal 3S.

When the train advances far enough to vacate section iT, track relay ITR picks up and establishes the circuit of relay IH, while contact 68 interrupts the stick circuit of relay iSR. On picking up of the contacts of relay iI-I contacts 25 and 3| establish connections to supply energy of normal polarity to the line circuit. This energy feeds to the line relays 31? and 3N and the contacts of relay 3P are shifted to their lefthand or normal positions so that contact 58 establishes the circuit of the green or clear lamp G of signal 3S.

From the foregoing, it will be seen that this invention provides means to simultaneously control two signals over a single line circuit. It will be seen also that the system is arranged so that the energy supplied to each end of the line circuit is independent of that supplied to the other end of the line circuit so that cutting off of the supply of energy to one end of the line circuit does not affect the energy supplied to the other end of the circuit.

In addition, it will be seen that the line circuit is not only interrupted by certain of the track relays, but is short circuited to prevent possible improper energization of the line relays in the event energy is improperly supplied to the line circuit.

Although the invention has been illustrated and described in connection with a railway signaling system, it is not limited to use for this purpose, but may be used wherever indications are to be transmitted simultaneously in opposite directions over a single line circuit.

Although I have herein shown and described only one form of remote control apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention what I claim is:

1. In combination, a pair of control conductors, a first coding device and a first electroresponsive means at one end of said control conductors, and a second coding device and a second electroresponsive means at the other end of said control conductors, each of said coding devices having a contact continuously actuated between a first and a second position, each of said coding devices having associated therewith means effective according as the contact of said device is in its first or its second position to connect a source of current or the associated electroresponsive means across said conductors, the contact of one of said coding devices being operated at a substantially diiferet rate than the contact of the other of said devices, whereby the contacts of said devices recurrently occupy positions to permit energy to be supplied over the control conductors to each of said electroresponsive means.

2. In combination, a pair of control conductors, a first coding device and a first electroresponsive device at one end of said control conductors, a second coding device and a second. electroresponsive device at the other end of said control conductors, each of said electroresponover the sive devices being selectively responsive to the polarity of the energy supplied thereto, each of said coding devices having a contact continuously actuated between a first and a second position, each of said coding devices having associated therewith means effective according as the contact of said device is in its first or its second position to connect a source of current or the associated electroresponsive device across said conductors, the contact of one of said coding devices being operated at a substantially different rate than the contact of the other of said devices, whereby the contacts of said devices recurrently occupy positions to permit energy to be supplied control conductors to each of said electro-responsive means, and means for selectively controlling the polarity of the energy supplied to end of the control conductors.

3. In a railway signaling system, in combination, a stretch of railroad track, a first signal governing entrance of trains moving in one direction into said track stretch, a second signal governing entrance of trains moving in the other direction into said track stretch, a pair of control conductors substantially coextensive with said track stretch, a first coding device and a first electroresponsive device at the end of the control conductors adjacent said first signal, and a second coding device and a second electroresponsive device at the end of the control conductors adjacent said second signal, each of said coding devices having a contact continuously actuated between a first and a second position, each of said coding devices having associated therewith means effective according as the contact of said device is in its first or its second position to connect a source of current or the associated electroresponsive device across said conductors, the contact of one of said coding devices being operated at a substantially different rate than the contact of the other of said devices, whereby the contacts of said devices recurrently occupy positions to permit energy to be supplied over the control conductors to each of said electro-responsive means, each of said electroresponsive devices controlling the associated signal.

4. In a railway signaling system, in combination, a stretch of railroad track, a first signal govei'ning entrance of trains moving in one direction into said track stretch, a second signal governing entrance of trains moving in the other direction into said track stretch, a pair of control conductors substantially coextensive with said track stretch, a first coding device and a first electroresponsive device at the end of the control condoctors adjacent said first signal, a second coding device and a second electroresponsive device at the end of the control conductors adjacent said second signal, each of said coding devices having a contact continuously actuated between a first and a second position, each of said coding devices having associated therewith means efiective according as the contact of said device is in its first or its second position to connect a source of current or the associated electroresponsive device across said conductors, the contact of one of said coding devices being operated at a substantially different rate than the contact of the other of said devices, whereby the contacts of said devices recurrentiy occupy positions to permit energy to be supplied over the control conductors to each of said electro-responsive means, each of said electroresponsive devices controlling the associated signal, and means governed by traflic conditions in said track stretch for controlling said control conductrs.

5. In a railway signaling system, in combination, a stretch of railroad track divided into a plurality of successive track sections including a first, an intermediate, and a second section, a first signal governing entrance of trains into the intermediate section from said first section, a second signal governing entrance of trains into the intermediate section from the second section, a pair of control conductors substatially coextensive with said intermediate section, a first coding device and a first electroresponsive device at the end of the control conductors adjacent said first signal, a second coding device and a second electroresponsive device at the end of the control conductors adjacent said second signal, each of said coding devices having a contact continuously actuated between a first and a second position, each of said coding devices having associated therewith means effective according as the contact of said device is in its first or its second position to connect a source of current or the associated electroresponsive device across said conductors, the contact of one of said coding devices being operated at a substantially different rate than the contact of the other of said devices, whereby the contacts of said devices recurrently occupy positions to permit energy to be supplied over the control conductors to each of said electro-responsive means, each of said electroresponsive devices controlling the associated signal, means effective on occupancy of the first section to interrupt the circuit including the contact of said first coding device for connecting the control conductors to said source of current, means ef fective on occupancy of the second section to interrupt the circuit including the contact of said second coding device for connecting the control conductors to said source of current, and means governed by trai'rlc conditions in said intermediate section and controlling said control conductors.

6. In a railway signaling system, in combination, a stretch of railroad track divided into a plurality of successive track sections including a first, an intermediate, and a second section, a first signal governing entrance of trains into the intermediate section from said first section, a second signal governing entrance of trains into the intermediate section from the second section, a pair of control conductors substantially coextensive with said intermediate section, a first coding device and a first electroresponsive device at the end or the control conductors adjacent said first signal, a second coding device and a second electroresponsive device at the end of the control conductors adjacent said second signal, each of said coding devices having a contact continuously actuated between a position in which it establishes connection from said control conductors to a source of current and a position in which it establishes connection from said control conductors to the associated electroresponsive device, each of said electroresponsive devices controlling the associated signal, means effective on occupancy of the first section to interrupt the connection including the contact of said first coding device for connecting said control conductors to said source of current and to connect said control conductors directly to said first electroresponsive means independent of said first coding device, means effective on occupancy of the second section to interrupt the connection including the contact of said second coding device for connecting said control conductors to said source of current and to connect said control conductors directly to said second electroresponsive device independent of said second coding device, and means governed by trafiic conditions in said intermediate section and controlling said control conductors.

7. In a railway signaling system, in combination, a stretch of railroad track divided into a first and a second track section, a first signal governing entrance of trains moving in one direction into said track stretch, a second signal governing entrance of trains moving in the other direction into said track stretch, a pair of control conductors substantially coextensive with said track stretch, a first coding device and a first electroresponsive device at the end of the control conductors adjacent said first signal, a second coding device and a second electroresponsive device at the end of the control conductors adjacent said second signal, each of said coding devices having a contact continuously actuated between a first and a second position, each of said coding devices having associated therewith means efiective according as the contact of said device is in its first or its second position to connect a source of current or the associated electroresponsive device across said conductors, each of said electroresponsive devices controlling the associated signal, and a track relay for each of said track sections, each track relay having a contact included in one of said control conductors, each track relay being efiective when its contacts are picked up to permit the circuit of said control conductors to be established and being effective when its contacts are released to short circuit the portions or the control conductors at each side of said track relay.

8. In a railway signaling system, in combination, a stretch of railroad track divided into successive sections including a first, an intermediate and a second section, a first signal governing entrance of trains into the intermediate section from said first section and a second signal governing entrance of trains into the intermediate section from the second section, a pair of control conductors substantially coextensive with said intermediate section, a first coding device and a first electroresponsive device at the end of the control conductors adjacent said first signal, a second coding device and a second electroresponsive device at the end of the control conductors adjacent said second signal, each of said coding devices having a contact continuously actuated between a first and a second position, each of said coding devices having associated therewith means efiective according as the contact of said device is in its first or its second position to connect a source of current or the associated electroresponsive device across said conductors, each of said electroresponsive devices being selectively responsive to the polarity of the energy supplied thereto and controlling the associated signal, said first and second sections each having means governed by traific conditions in said section and controlling the supply of energy to the adjacent end of said control conductors, each such means being effective when the associated section is vacant to permit energy of one polarity to be supplied to said control conductors, each such means being effective when the associated section is occupied by a train approaching said intermediate section to interrupt the supply of energy to said control conductors and being effective when the associated section is occupied by a train leaving said intermediate section to permit energy of the opposite polarity to be supplied to said control conductors.

9. In a railway signaling system, in combination, a stretch of railroad track divided into successive sections including a first, an intermediate and a second section, a first signal governing entrance of trains into the intermediate section from said first section and a second signal governing entrance of trains into the intermediate section from the second section, a pair of control conductors substantially coextensive with said intermediate section, a first coding device and a first electroresponsive device at the end of the control conductors adjacent said first signal, a second coding device and a second electroresponsive device at the end of the control conductors adjacent said second signal, each of said coding devices having a contact continuously actuated between a position in which it establishes connection from said control conductors to a source of direct current and a position in which it establishes connection from said control conductors to the associated electroresponsive device, each of said electroresponsive devices being selectively responsive to the polarity of the energy supplied thereto and controlling the associated signal, said first and second sections each having means governed by traffic conditions in said section and controlling the supply of energy to the adjacent end of said control conductors, each such means being effective when the associated section'is vacant to permit energy of one polarity to be supplied to said control conductors, each such means being effective when the associated section is occupied by a train approaching said intermediate section to interrupt the supply of energy to said control conductors and being effective when the associated section is occupied by a train leavin said intermediate section to permit energy of the opposite polarity to be supplied to said control conductors, and means governed by traffic conditions in said intermediate section and controlling said control conductors.

GEORGE W. BAUGHMAN.

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