US1031529A - Block-signaling system and safety apparatus. - Google Patents

Block-signaling system and safety apparatus. Download PDF

Info

Publication number
US1031529A
US1031529A US46507208A US1908465072A US1031529A US 1031529 A US1031529 A US 1031529A US 46507208 A US46507208 A US 46507208A US 1908465072 A US1908465072 A US 1908465072A US 1031529 A US1031529 A US 1031529A
Authority
US
United States
Prior art keywords
block
motor
signal
train
semaphore
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US46507208A
Inventor
Mark Conrad
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ANNA CONRAD
GEORGE W CONRAD
WILLIAM G KELLY
Original Assignee
ANNA CONRAD
GEORGE W CONRAD
WILLIAM G KELLY
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ANNA CONRAD, GEORGE W CONRAD, WILLIAM G KELLY filed Critical ANNA CONRAD
Priority to US46507208A priority Critical patent/US1031529A/en
Application granted granted Critical
Publication of US1031529A publication Critical patent/US1031529A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B61RAILWAYS
    • B61LGUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
    • B61L3/00Devices along the route for controlling devices on the vehicle or vehicle train, e.g. to release brake, to operate a warning signal
    • B61L3/02Devices along the route for controlling devices on the vehicle or vehicle train, e.g. to release brake, to operate a warning signal at selected places along the route, e.g. intermittent control simultaneous mechanical and electrical control
    • B61L3/08Devices along the route for controlling devices on the vehicle or vehicle train, e.g. to release brake, to operate a warning signal at selected places along the route, e.g. intermittent control simultaneous mechanical and electrical control controlling electrically
    • B61L3/10Devices along the route for controlling devices on the vehicle or vehicle train, e.g. to release brake, to operate a warning signal at selected places along the route, e.g. intermittent control simultaneous mechanical and electrical control controlling electrically using current passing between devices along the route and devices on the vehicle train

Definitions

  • LJ [LL accidents at crossings and switches, thus are automatically released by 'electro-mag-- invention comprises the various novel leaf.
  • a i j- This' invention relates to bloclr.L signaling systems adapted for use on steam or electric in its operation for preventing head-on or rear-end collisions onsingletra'clr lines or dispensingwith, the usual telegraph ⁇ and block otlices with theirv operatorsoand signalrnen and dispensing also with the train despatcher.
  • the invention liasfor oneot itsl objects to improve and simplify the construction and operation of signal systems of this character so as tofbe comparativelysiniple and inexpensive to manufacture and install," thoroughly reliablea and etlicient in use, and enti-rely automat-ic ',inl operation. f
  • Another object ot' fthe' invention is the provision of ajsignal system in which each block has a semaphore, target or the like, at bothends, in connection with electrical devices and circuits whereby the signal at the far or v'leaving end of the block will loe set to danger position a suitable period, in
  • Figure- 1 is a diagrammatic view oifthef v va vane r arm b shaft 5.
  • Fig@ is a side view of the locking device for holding a semaphore in danger position.
  • Fig. 3 is a detail sectional view. of.
  • Fig. 5 is a diagrammatic Viewotla .track switch showing means for grounding the third railfor the circuits of the emergency stopping system.
  • Fig. 6 is a diagrammatic View or a crossing Vot two tracks showing the arrangement of the third rails or conductors.
  • l and. 2 designate the main rails of a track which is divided into blocks and at the'ends of adjacent blocks are insulated rail sections c and a in the opposite rails that are con nected with the circuits of one block andin i one ot the rails at each end of the blockl is an insulated rail section b for connection with the circuits of adjacent blocks, ,as will be hereinafter explained.
  • the blocks are signaling devices ,A and B' arranged some distance inwardly from the ends of the block so that the 'signals Will operate before a train reachesthe signal and after vit enters the block.
  • the signals are operated'and controlled in such a manner that .the signalat the leaving end of the block will operate in advance of, that at the entrance end so that by this means, the opposite end oit the block will be'guardedagainst the entrance of a train approaching in the opposite di* rection andl thereby prevent a head-on collision.
  • Eaehsignal device comprises in the present instance a semaphore ⁇ consisting ot "for sigiall-ing. by day and a colored glass or other targetlt tor signaling hy night, the semaphore being mounted to swing ⁇ to and from dangerfpcsition on an arm or vane 3 ispio ided with a weight 31? to oyerbalance theft i fet Il; so
  • the shaft 5 in any suitable manner, so that when the motor is energized, the semaphore willbc raised from inclined to horizontal or danger position.
  • the semaphore is releasably held in the danger position by a locking device C, which consists of a ratchet wheel 6 on the shaft 5 of the semaphore, 'with which cooperates a spring-pressed pawl ,7 located adjacent the wheel to engage the teeth thereof :tor prevent-ing the semaphore from ⁇ dropping to clear, track position, said pawls being left ⁇ out of Fig. 1 forclearness of illustration of adjacent parts.
  • the pawl 7, as shown in Figs. 2 and 3 is mounted on an armature 8 of the pawl-releasing electroemagnet 9.
  • the electro-magnet is provided with yoke bars 10 on which is guided the central stem A12 of the armature, andvon this stem is a spring 13 which bears against the collar 14; on the stem and against the yoke 11 to force the pawl upwardly and held it in engagement with the ratchet Wheel 6.
  • each motor M ' is a circuit closer consisting of a fixed contact 15 and a swinging contact 16 connected with the shaft 5 of the semaphore and so arranged as to engage the contact 15 as the semaphore reaches danger position.
  • the circuit of the motor for the semaphore at the leaving end of a block is closed automatically as the train enters the block and by the time the semaphore reachesdanger position, the circuit closer thereof will close the circuit of the motor for the semaphore at the entrance end of the block for operating such semaphore to indicate to the engineer ofthe approachingY train that the system is in working order and that the semaphore at the leaving end of the block has been raised to danger position; otherwise the circuit for the motor of the semaphore at the entrance end of the block would not be closed.
  • a t each signal, a relay Ris employed for closing the motor* circuit of the opposite i signal and the relays are energized by current derived from a generator or battery on' the locomotive of the train, the source of current being connected in any suitable manvner by wheels with the rails of the track.
  • signals operate in reverse order to that above described. That is to say, the signal' Aiwill operate iirst as the train enters the l block and then the signal B will be operated.
  • the signals V will be held in danger position as long as the trainis in the block andv as the train leaves the block, circuits will be established for energizing the pawl-releassignals can drop by gravity to clear 'posi-4 l tion.
  • each rail section a Connected with each rail section a is a-wire 30 that is connected to ground at 31 and included in this wireis anelectro- .magnet 32 for closing a Switchs', the movable element otwlbich is mechanically connectedv withand insulated from the movable element of the adjacent switch s by '5a strip 33, so that the motor circuit of a signal will
  • the current for energizing the electro-magnets 32 is derived froml the generator or other source on the locomotive and as soon as the Wheels on the locomotive contact With the rail section a, the vcurrent will iiow from the one terminal of the generator on the locomotive ⁇ through the rail section cz, Wire 3G, electro-magnet 32, 'ground 3l, ground g2, Wire 37, rail section 2 (if the train be entering the block at A), and back to the other terminal of the generator on the locomotive.
  • the electro-mag, net 32 becomes derergized by the Wheels passing oli'
  • F ig. 5 represents a diagram of a4 track switch of which l and 2 are the main rails, and 5l and 52 the rails of a siding Vorl branch track, the-switch points 53 being operated .by a rod 54e connected with a switch stand 55 of any approved construction.
  • the third'rail il will be connected to ground by a switch that includes 'a blade 56 on the switch-stand and contacts '57, the blade being connected to ground by a Wire 58 and the contact 57 connected to the third rail by a Wire 59.
  • Fig. 6 is a diagram cfa track crossing Whiclishows the third rails il oi both tracks electrically connected by a Wire 7,0so that v vboth tracks which intersect each other at .the crossing, will close the motor circuits ofthe emergency stopping devices and thus bring the trains to rest-in time to avoid an accident.
  • the combinationot separate signals, an electric motor for moving each signal to danger position against the' attract-ion of gravity, circuits for the motors, a relay for closing the Vcircuit ofthe motor at the leaving end of the block, a circuit'for the relay adapted to be completed by a train passing into the block, a circuit closer closed by the operation of the-motor at the leaving end oi the block for closing the Vcircuit ot' the motor at the entrance end thereof, locking devices ior holding the signals in set position, electromagnets for releasing the said devices,h a circuit for the electro-magnets, normally open switches in the last-mentioned circuit, and electrical means at the ends of the block adapted to lbe energized by the passage of the train out of the block tor closing said switches to energize the releasing magnets.
  • a block signaling system the combination with a track having insulated sections and a train adapted to enter upon said insulated track sections, of a source of current carried by the train, means for connecting said source oi current with said insulated sections a signal at the entering andv at the leaving end of the block, an electric motor Jfor each. signal, a relay at cach signal station for controlling the motor at the other station, partial circuits for the relays arranged to be closed by the entrance of a train on certain yoit said insulated-sections, locking means for said signals, and circuits including releasing devices for said signal locking means arranged to be closed by the passage oit a train oyer certain
  • the com- 4 train ori-certain of said insulated' sections and locking means for said signals.
  • a block signaling system the conibination with a trackhaving insulated sections and a train adapted to enter upon said insulated track sections, of a source oit current carried by the train, means for connecting said source of current With'said insulated sections a si nal at the entering' and at the leaving end of the block, an elec tric motor for each signal, a relay at each signal station for controlling the motor at the other station, and partial circuits for the relays arranged to be closed by the entrance or" a train on certain ot said insulated sections.

Description

M. CONRAD.
BLOCK SIGNALING SYSTEM ANDl SAFETY APPARATUS.
APPLICATION FILE-D NOV.30. 1908.
2 SHEETS-SHEET 1.
' Patented July 2,1912.
M.A CONRAD. BLOCK SIGNALING SYSTEMAND SAFETY APPARATUS.
APPLIGALIO1\I FILED NOV.30.1908. 1,931,529. Patented July 2,1912.
2 SHEETS-SHEET 2.
ihr l.
LJ [LL accidents at crossings and switches, thus are automatically released by 'electro-mag-- invention comprises the various novel leaf.,
vMichigan, have invented new and useful roadsand designed to be entirely automatic the block. ll (l.
entren erna Manie Conni-in, or AnnrAN, Ivrrcrrrean, asistencia or CONRAD Ann cnn-FOURTH 'ro ANNA Gennaio, :Born
ONE-HALF TO 'WILLIAM G. KELLY, GF WID/SLOW, .AREZNA.
BLQCK-SIGNAING 'SYSTEM ANB SFETY APPARATUS,
resinas.
4Specification of Letters Patent.
rammen amy a, tera Application 1erl`lovember 80, i996. Serial No. 465,072.
To all whonwt may concern:
Be it known that l, MARKv CONRAD',4 a citizen ofthe United States, residing at Adrian, in the county of Lenawee and State ot Improvements in Block-Signalinw- Systems' and Safety Apparatuantwhich p c :followingisaspecitication. A i j- This' invention relates to bloclr.L signaling systems adapted for use on steam or electric in its operation for preventing head-on or rear-end collisions onsingletra'clr lines or dispensingwith, the usual telegraph `and block otlices with theirv operatorsoand signalrnen and dispensing also with the train despatcher. i
The invention liasfor oneot itsl objects to improve and simplify the construction and operation of signal systems of this character so as tofbe comparativelysiniple and inexpensive to manufacture and install," thoroughly reliablea and etlicient in use, and enti-rely automat-ic ',inl operation. f
Another object ot' fthe' invention is the provision of ajsignal system in which each block has a semaphore, target or the like, at bothends, in connection with electrical devices and circuits whereby the signal at the far or v'leaving end of the block will loe set to danger position a suitable period, in
advance' of the operation ot thesignal at the entrance end ofthe block, both' signals being'held in danger position against the attraction hf gravity by locking devices that nets connected in circuit as thetrain leaves 'lilith these' objects in view and others, as will appear as the description proceeds, the
tures ot' construction and arrangement of" parts which" will be more fully.described hereinafter and set forth with particularity in the claims appended hereto.
ln the accompanying drawings, which illustrate one embodiment ot the invention,
Figure- 1 is a diagrammatic view oifthef v va vane r arm b shaft 5. The
teni as applied to one hloclr oa single track line. Fig@ is a side view of the locking device for holding a semaphore in danger position. Fig. 3 is a detail sectional view. of.
the locking device. .Figari-isa diagrtnrnrnatie- View of the track showing two vtrains there on in a single block. together with thecir-jcuit connections. Fig. 5 is a diagrammatic Viewotla .track switch showing means for grounding the third railfor the circuits of the emergency stopping system. Fig. 6 is a diagrammatic View or a crossing Vot two tracks showing the arrangement of the third rails or conductors.
Similar reference characters are ern--v ployed to designate corresponding parts throughoutA the views'. Q
Reterring to Fig. l of the drawing, l and. 2 designate the main rails of a track which is divided into blocks and at the'ends of adjacent blocks are insulated rail sections c and a in the opposite rails that are con nected with the circuits of one block andin i one ot the rails at each end of the blockl is an insulated rail section b for connection with the circuits of adjacent blocks, ,as will be hereinafter explained.
At the ends of the blocks are signaling devices ,A and B' arranged some distance inwardly from the ends of the block so that the 'signals Will operate before a train reachesthe signal and after vit enters the block. for the purpose of warning the engineer thatthe vsystem is in perfect operation The signals are operated'and controlled in such a manner that .the signalat the leaving end of the block will operate in advance of, that at the entrance end so that by this means, the opposite end oit the block will be'guardedagainst the entrance of a train approaching in the opposite di* rection andl thereby prevent a head-on collision. Eaehsignal devicecomprises in the present instance a semaphore `consisting ot "for sigiall-ing. by day and a colored glass or other targetlt tor signaling hy night, the semaphore being mounted to swing` to and from dangerfpcsition on an arm or vane 3 ispio ided with a weight 31? to oyerbalance theft i fet Il; so
that the sennibhore will return to normal or electric motor M operatively connected with the locomotive through the rail'section a',
the shaft 5 in any suitable manner, so that when the motor is energized, the semaphore willbc raised from inclined to horizontal or danger position.
v The semaphore is releasably held in the danger position by a locking device C, which consists of a ratchet wheel 6 on the shaft 5 of the semaphore, 'with which cooperates a spring-pressed pawl ,7 located adjacent the wheel to engage the teeth thereof :tor prevent-ing the semaphore from `dropping to clear, track position, said pawls being left` out of Fig. 1 forclearness of illustration of adjacent parts. The pawl 7, as shown in Figs. 2 and 3, is mounted on an armature 8 of the pawl-releasing electroemagnet 9. The electro-magnet is provided with yoke bars 10 on which is guided the central stem A12 of the armature, andvon this stem is a spring 13 which bears against the collar 14; on the stem and against the yoke 11 to force the pawl upwardly and held it in engagement with the ratchet Wheel 6.
At each motor M 'is a circuit closer consisting of a fixed contact 15 and a swinging contact 16 connected with the shaft 5 of the semaphore and so arranged as to engage the contact 15 as the semaphore reaches danger position. By means of these circuit closers, the operation of one motor precedes that ofthe other motor, as will be described hereinafter. In other words, the circuit of the motor for the semaphore at the leaving end of a block is closed automatically as the train enters the block and by the time the semaphore reachesdanger position, the circuit closer thereof will close the circuit of the motor for the semaphore at the entrance end of the block for operating such semaphore to indicate to the engineer ofthe approachingY train that the system is in working order and that the semaphore at the leaving end of the block has been raised to danger position; otherwise the circuit for the motor of the semaphore at the entrance end of the block would not be closed.
A t each signal, a relay Ris employed for closing the motor* circuit of the opposite i signal and the relays are energized by current derived from a generator or battery on' the locomotive of the train, the source of current being connected in any suitable manvner by wheels with the rails of the track.
As a train enters the block, the wheels will make cont-act with the rail section aand the opposite grounded portion of the rail 1, and current then flows from the source on Wire' 17, relay B, wire 18, ground g, to
ground gf; wire 19, rail 1, and back to the source of'current on the locomotive. The relay is thus energized and closesthe armature 2O thereof which forniy part of the switch S for closing the circ it ct the motor for the semaphore at the end ci' the block.- In each motor circuit is shown bat--- tery 21, although, it desired, the! current may be derived from a power circuit ex* tending along the railroad. When a train enters the block station A, the switch S of the relay at such stationjwillbe closed' and current will pass from the battery 21 at the station B through the wire 22, the switch s, wire 23, brush 211 of the motor at the. station B, motor M, brush 25, wire 26a, switch S, y wire 27, wire 28 which is connected with the opposite side of the battery 21 at thesignal B. The motor at the signal B will thus be actuated so as to bring the semaphore to. danger position. During this movement of the semaphore, the contact 16 of the circuit closer will engage the Contact 15 so as to connect the motor at the signal A in circuit with its battery. Current now Hows from the battery 21 at the signal Ar through the wire 28, wire 27, thence to theoppositeend of the block at the signal B, through the contacts 15 and 16 ci the circuit closer at such signal, through the wires 29 and 26,
through the. latter wire backto the signal A,
brush 25 oit the motor of the signal',
through theniotor, brush 24, wire 23, switch 9 s, Wire ,22, and to the 'other sideof the batprotect'tie train ahead and'behind while iii the block. When a train enters the block at the end where the signal B is located, the
signals operate in reverse order to that above described. That is to say, the signal' Aiwill operate iirst as the train enters the l block and then the signal B will be operated.
The signals Vwill be held in danger position as long as the trainis in the block andv as the train leaves the block, circuits will be established for energizing the pawl-releassignals can drop by gravity to clear 'posi-4 l tion. Connected with each rail section a is a-wire 30 that is connected to ground at 31 and included in this wireis anelectro- .magnet 32 for closing a Switchs', the movable element otwlbich is mechanically connectedv withand insulated from the movable element of the adjacent switch s by '5a strip 33, so that the motor circuit of a signal will The current for energizing the electro-magnets 32 is derived froml the generator or other source on the locomotive and as soon as the Wheels on the locomotive contact With the rail section a, the vcurrent will iiow from the one terminal of the generator on the locomotive `through the rail section cz, Wire 3G, electro-magnet 32, 'ground 3l, ground g2, Wire 37, rail section 2 (if the train be entering the block at A), and back to the other terminal of the generator on the locomotive. As soon as the electro-mag, net 32 becomes derergized by the Wheels passing oli' the rail section a, the switches s and e Will return to normal position.
F ig. 5 represents a diagram of a4 track switch of which l and 2 are the main rails, and 5l and 52 the rails of a siding Vorl branch track, the-switch points 53 being operated .by a rod 54e connected with a switch stand 55 of any approved construction. `When the switchl points are thrown to open thesivitch, the third'rail il will be connected to ground by a switch that includes 'a blade 56 on the switch-stand and contacts '57, the blade being connected to ground by a Wire 58 and the contact 57 connected to the third rail by a Wire 59. By, this arrangement, the third rail of the mainA line'vvill `be connected in circuit as longas the track switch remains open, so that a tram traveling on the main line will be Abrought to rest by its emergencyistopping devices bei-ore the switch is reached.
Fig. 6 is a diagram cfa track crossing Whiclishows the third rails il oi both tracks electrically connected by a Wire 7,0so that v vboth tracks which intersect each other at .the crossing, will close the motor circuits ofthe emergency stopping devices and thus bring the trains to rest-in time to avoid an accident.
Having thus described the invention," what claim is 1.'.In a block signal system, the combination of signals at the ends of the block, a motor for actuating each signal, circuits tor the motors, devices controlled by the eu trance of a train inthe block for closing the circuit of the motor at the leaving end of the block, means for -closing the circuit of the other motor by the movement of the signal at the leaving end of the block, lockingdevices for holding thesignals in set position, switches for cutting the locking devices into and out of circuit and for opening and closing the motor circuits, an electro-1nagnet energized as the train leaves the block for operating the switches.
2. in a block signal system, the combinationot separate signals, an electric motor for moving each signal to danger position against the' attract-ion of gravity, circuits for the motors, a relay for closing the Vcircuit ofthe motor at the leaving end of the block, a circuit'for the relay adapted to be completed by a train passing into the block, a circuit closer closed by the operation of the-motor at the leaving end oi the block for closing the Vcircuit ot' the motor at the entrance end thereof, locking devices ior holding the signals in set position, electromagnets for releasing the said devices,h a circuit for the electro-magnets, normally open switches in the last-mentioned circuit, and electrical means at the ends of the block adapted to lbe energized by the passage of the train out of the block tor closing said switches to energize the releasing magnets.
3. Ina block signaling system, the combination with a track having insulated sections and a train adapted to enter upon said insulated track sections, of a source of current carried by the train, means for connecting said source oi current with said insulated sections a signal at the entering andv at the leaving end of the block, an electric motor Jfor each. signal, a relay at cach signal station for controlling the motor at the other station, partial circuits for the relays arranged to be closed by the entrance of a train on certain yoit said insulated-sections, locking means for said signals, and circuits including releasing devices for said signal locking means arranged to be closed by the passage oit a train oyer certain| -other oftl said insulated sections. 1
4. Ina block signaling syst-ein, the com- 4 train ori-certain of said insulated' sections and locking means for said signals.
In a block signaling system, the conibination with a trackhaving insulated sections and a train adapted to enter upon said insulated track sections, of a source oit current carried by the train, means for connecting said source of current With'said insulated sections a si nal at the entering' and at the leaving end of the block, an elec tric motor for each signal, a relay at each signal station for controlling the motor at the other station, and partial circuits for the relays arranged to be closed by the entrance or" a train on certain ot said insulated sections.
6. l'n a block signaling system, the cenif meeting said source of' Current with said` n- A ssulatedy sect-lons, e slgnal at the Ventermg ltnesses:
binaton. with a track having insulated sec? each signal station 'for controlling the motor tiensend a treinadap'ted-to enter upon said' at the other station. Y 10 insulated trackectons, o" a Ysource of curn'testmony whereof l'afix my signature Y reni: carried by thetran, means for '00nn presence of tWo Witesses. f
'MARK 01513@ and at the leaving end o" the block, an 'elee- JOHN LQ FLE'HER tmc motor for each slgnal, and a relay at l C.' BRADWAY.
US46507208A 1908-11-30 1908-11-30 Block-signaling system and safety apparatus. Expired - Lifetime US1031529A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US46507208A US1031529A (en) 1908-11-30 1908-11-30 Block-signaling system and safety apparatus.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US46507208A US1031529A (en) 1908-11-30 1908-11-30 Block-signaling system and safety apparatus.

Publications (1)

Publication Number Publication Date
US1031529A true US1031529A (en) 1912-07-02

Family

ID=3099821

Family Applications (1)

Application Number Title Priority Date Filing Date
US46507208A Expired - Lifetime US1031529A (en) 1908-11-30 1908-11-30 Block-signaling system and safety apparatus.

Country Status (1)

Country Link
US (1) US1031529A (en)

Similar Documents

Publication Publication Date Title
US1031529A (en) Block-signaling system and safety apparatus.
US556072A (en) Geoege l
US737094A (en) Controlling system for railway-signals.
US763420A (en) Automatic signaling system for railways.
US774618A (en) Electrically-operated block-signaling apparatus.
US1018443A (en) Block-signaling system for electric railways.
US662833A (en) Railway signaling.
US1195748A (en) sutphin
US1457192A (en) Electric safety system for railroads
US1060403A (en) Electric train signaling and controlling means.
US852633A (en) Train-stopping apparatus.
US1197749A (en) Railway signaling.
US802583A (en) Electric railway-signal.
US912301A (en) Block-signalling system.
US798784A (en) Control of apparatus governing the passage of cars along railways.
US759543A (en) Electric railway-signal.
US869785A (en) Electrically-operated signal for railroads.
US838848A (en) Signal device.
US143529A (en) Improvement in electric circuits and devices for railway-signals
US756511A (en) Electric railway.
US1266405A (en) Railway signal and train-stop system.
US447906A (en) Electric railway-signal
US457135A (en) Railway-signal
US1223685A (en) Permissive automatic train-stop.
US1231540A (en) Railway signaling system.