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the disadvantage of a relatively low distance between points and signal box (approximately 200–250 m) and a slow operating speed. It was common in Italy and France only. Pneumatic lever frames have an operating principle that is related to that of hydraulic lever frames, however, instead of a hydraulic liquid, compressed air is used. The two types also share the same disadvantages such as pressurized tubing having to run directly between the field appliance and the lever frame. Electric control of a hydraulic or pneumatic actuator in the field was far simpler and more reliable, allowing for a greater distance between signal box and points. Whilst first being common in the United States due to work by the
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behind it. This may be accompanied by a description of the lever's function. Usually, a large track diagram is positioned within easy view of the operator, which clearly shows each lever number adjacent to symbols representing the items of equipment that they operate. Levers are commonly coloured according to the type of equipment they control, the code of colours varying between different railway administrations. For example, in
British practice, the following code generally applies: a red lever controls a stop signal or shunt signal, a yellow lever controls a distant signal, a black lever controls a set of points, a blue lever controls a
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205:, and a white lever is spare. Brown levers are used to lock level crossing gates. Lever handles are usually of polished, unpainted steel, and signalmen operate them with a cloth to prevent rusting from the sweat on their hands. In Germany, signal levers are red, whilst levers for points and track locks are usually blue, and route lock levers are green. Also, individual numbers and letters are used to indicate each individual item a lever operates in Germany as well.
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103:, Germany: the signals are operated by the red levers, black levers with Arabic numerals are for points and blue levers with Roman numerals are for track locks. The box on the right of the lever frame is used for manual block signalling; the smaller green levers are used for operating the route locks. The interlocking apparatus is in the box behind the levers.
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In hydraulic lever frames, moving the lever operates a hydraulic valve rather than wires and rods. To prevent accidents, operating a set of points requires pulling the actual lever for the points and a secondary check lever. The points are then moved by a hydraulic motor. This type of power frame has
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To assist the operator in determining their functions, each lever in a frame will generally be uniquely labelled, one common method being to number the levers in order from left to right. A lever's identification may be painted on its side or engraved on a badge or plate fitted either to the lever or
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logic. The levers are connected to field appliances via solid pipes or taut wires such that the full travel of the lever will reliably cause full travel in the appliance. Each lever is engaged with the interlocking logic such that movement of the lever is only possible when all necessary conditions
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next to the track, without any form of shelter and were usually operated by traincrew and not permanently staffed. Especially in
England, lever frames with the pivot underneath the floor of the signal box were common. This design's relatively short lever angle is a major disadvantage, as it requires
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A major issue with power frames was ensuring that the position of the levers on the frame correctly represented the position of the switch or other appliance in the field. Unlike a mechanical linkage, pneumatic or hydraulic lines could leak and cause points to drift out of correspondence with
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designed in the 19th and early 20th centuries to save on costly relays, were replaced by closed loop systems after a number of accidents. In North
America this is known as "Switch-Signal" protection and any change in the position of a field appliance will immediately set the electric signals
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Some mechanical frames were combined with a set of electric levers or switches to more efficiently work electrically powered signals or other non-mechanically operated devices. Typically the switch points would be left under mechanical operation as the other devices used comparatively little
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designed to ensure that the levers cannot be operated to create a conflicting train movement. Each interlocking installation is individual and unique to the location controlled. The interlocking may be achieved mechanically or by electric lever locks, or (more usually) a combination of both.
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In
Austria, Siemens & Halske built a fully electric power frame in 1894, which does not rely on compressed air. Instead, electric motors move the points. Later, this system was also used in Germany. In the United States the Taylor Signal Corporation, later merged into
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A power operated interlocking frame uses some form of power assist to operate switches, signals and other interlocking appliances in the field. The power can come from hydraulic, pneumatic or electric sources with direct acting or low voltage electric control.
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developed an electrically powered interlocking system that made use of mechanical slides to engage traditional mechanical locking. Union Switch and Signal later modified their electro-pneumatic system to all-electric as early as 1896.
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generated when the electric motor reached the limit of travel would signal the interlocking logic that the points had finished moving, but not the position of the points on an ongoing basis. This and other
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The lever frame is located in the signal box, which can be a building at ground level or a tower, separated from or connected to an existing station building. Early lever frames were also built as
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more force to move the lever. Therefore, later, especially in
Germany, lever frames with pivots inside the signaller's room were used, that allow for a lever angle of approximately 180°.
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This place is fairly unique these days in being double-manned, but with 92 levers to operate it keeps us fairly busy and you soon work through the shoe leather.
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View of the frame in the locking room showing how it is installed within the signal box. Oulton Broad Swing Bridge signal box, Lowestoft, UK
246:), this system was later used in the United Kingdom and other Commonwealth nations where the Westinghouse Air Brake Company had a presence.
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and signals to operate, which will control the movement of each train through their area of control. The lever frame contains
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disastrous consequences. The Taylor/GRS electric power frame system used a feature called "dynamic indication" where the
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87:, England, and has 180 levers; although most of them have now been taken out of use.
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Derby Road Signal box, Ipswich, UK, showing the McKenzie & Holland frame, taken in 1997. Opened in 1891 by the
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Bahnsicherungstechnik: Steuern, Sichern und Überwachen von
Fahrwegen und Fahrgeschwindigkeiten im Schienenverkehr
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Everglades
Junction signal box with its Westinghouse Brake & Signal Co. Ltd. Style 'L' Power Lever Frame
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over waterways are operated via wires and rods. The signaller chooses the correct combination of points,
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electrical power and could be run off of batteries or a low capacity railroad-operated power system.
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Cauer, Wilhelm Adolf Eduard (1922). Otzen, Robert (ed.). "Sicherungsanlagen im
Eisenbahnbetriebe".
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to allow the safe operation of trains in the area the signals control. Usually located in the
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By the movement of individual levers (or sometimes cranks), signals, points, track locks,
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Another view in the locking room at Oulton Broad Swing Bridge, Lowestoft, UK
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Railway Signal
Company lever frame at Cromer Beach signal box, Cromer, UK
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The world's largest lever frame is believed to have been in the
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Director of S&T Engineering, West
Midlands Project Group
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Fenner, Wolfgang; Naumann, Peter; Trinckauf, Jochen (2011).
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are met. The interlocking may be mechanical, electric (via
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Spencer Street No.1 signal box in Melbourne, Australia
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lever frame at Eastgates signal box, Colchester, UK
36:A mechanical lever frame inside the signal box at
615:Westinghouse Miniature Power Lever Frame web site
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452:(in German). John Wiley & Sons. p. 89.
180:A mechanical lever frame is designed to harness
475:"From the Files: Shrewsbury's Record-Breakers"
188:, signals or both under the protection of the
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430: – British railway signalling technology
953:Interoperable Communications Based Signaling
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888:Automatic Train Protection (United Kingdom)
313:Mechanical lever frame in Hancock tower, US
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545:"South Devon Railway – Railway Signalling"
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134:gates or barriers and sometimes navigable
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598:Railroad Operation and Railway Signaling
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64:, the levers are operated either by the
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1013:Train Protection & Warning System
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52:for their operation to interlock the
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579:Railway Signaling and Communications
575:"The Principles of Electric Locking"
428:Integrated Electronic Control Centre
1008:Train automatic stopping controller
928:Continuous Automatic Warning System
27:Railway signalling system component
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688:Communications-based train control
416:. Abolished and demolished in 1999
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523:. Berlin/Heidelberg: Springer.
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993:Sistema Controllo Marcia Treno
903:Automatische treinbeïnvloeding
789:Application of railway signals
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400:Signal box interior, Truro, UK
244:Westinghouse Air Brake Company
111:A three-lever ground frame at
99:Lever frame of the signal box
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978:Punktförmige Zugbeeinflussung
698:European Train Control System
573:Anderson, James (July 1916).
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229:Power frame, type Siemens M43
918:Chinese Train Control System
708:Radio Electronic Token Block
174:Lüdinghausen railway station
164:Truro Signal Box lever frame
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683:Centralized traffic control
585:(7). Simmons-Boardman: 209.
473:Stephen, Paul (July 2018).
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300:Isle of Wight Steam Railway
298:Inside a signal box on the
261:counter-electromotive force
242:corporation (a division of
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1358:Railway signalling control
883:Automatic train protection
621:"Mechanical Interlocking."
337:Oban, Saskatchewan, Canada
325:Signal levers, Switzerland
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1033:Transmission Voie-Machine
878:Automatic train operation
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240:Union Switch & Signal
973:Pulse code cab signaling
898:Automatic Warning System
804:Railway semaphore signal
766:Solid State Interlocking
873:Automatic train control
596:Phillips, Edmund John.
156:Mechanical lever frames
1049:Level crossing signals
968:Positive Train Control
963:Linienzugbeeinflussung
693:Direct traffic control
350:McKenzie & Holland
286:Signal box lever frame
252:General Railway Signal
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718:Track Warrant Control
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182:mechanical advantage
600:. pp. 155–158.
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266:open loop systems
203:facing point lock
16:(Redirected from
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1105:General Electric
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558:20 September
556:. Retrieved
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482:. Retrieved
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18:Ground frame
1327:Switzerland
1302:New Zealand
1297:Netherlands
1003:Slide fence
756:Lever frame
184:to operate
44:Mechanical
1235:By country
1018:Train stop
983:RS4 Codici
741:Block post
435:References
85:Shrewsbury
62:signal box
40:in Ireland
1242:Australia
1095:AŽD Praha
1054:Crossbuck
958:Crocodile
195:solenoids
70:pointsman
66:signalman
1352:Category
1332:Thailand
1140:Safetran
1130:Magnetic
1115:Griswold
1064:E-signal
422:See also
151:Variants
91:Overview
1277:Germany
1267:Finland
1252:Belgium
1247:Bavaria
1150:Siemens
1125:Hitachi
1100:Federal
1085:Adtranz
988:SelTrac
835:Treadle
781:Signals
68:or the
54:signals
1322:Sweden
1317:Poland
1312:Norway
1282:Greece
1272:France
1257:Canada
1160:Thales
1090:Alstom
1059:Wigwag
938:EBICAB
908:Balise
527:
456:
58:points
1292:Japan
1287:Italy
1262:China
1196:AREMA
1145:Saxby
998:SACEM
943:IIATS
868:ATACS
713:Token
1216:IRSE
1211:HMRI
1120:Hall
863:ASFA
858:ALSN
560:2018
525:ISBN
486:2018
454:ISBN
1226:UIC
1206:FRA
1201:ERA
1191:AAR
1110:GRS
83:in
1354::
581:.
577:.
551:.
547:.
497:^
488:.
477:.
72:.
649:e
642:t
635:v
583:9
562:.
533:.
462:.
176:)
20:)
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