Lever frame

A mechanical lever frame inside the signal box at Knockcroghery in Ireland
Waterloo station A signalbox, LSWR (Howden, Boys' Book of Locomotives, 1907)

Mechanical railway signalling installations rely on lever frames for their operation to interlock the signals, track locks[1] and points to allow the safe operation of trains in the area the signals control. Usually located in the signal box, the levers are operated either by the signalman or the pointsman.[citation needed]

The world's largest lever frame is believed to have been in the Spencer Street No.1 signal box in Melbourne, Australia, which had 191 levers, but was decommissioned in 2008.[citation needed] The largest, currently operational, lever frame is located at Severn Bridge Junction in Shrewsbury, England, and has 180 levers; although most of them have now been taken out of use.[2]

  1. ^ Fenner, Wolfgang; Naumann, Peter; Trinckauf, Jochen (2011). Bahnsicherungstechnik: Steuern, Sichern und Überwachen von Fahrwegen und Fahrgeschwindigkeiten im Schienenverkehr (in German). John Wiley & Sons. p. 89. ISBN 9783895786839.
  2. ^ Stephen, Paul (July 2018). "From the Files: Shrewsbury's Record-Breakers". RailMagazine.com. Retrieved 20 September 2018. 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.