Annett's key
![](http://upload.wikimedia.org/wikipedia/commons/thumb/0/00/Ground_frame_kyle.jpg/170px-Ground_frame_kyle.jpg)
Groundframe, with the two rightmost levers locked by Annett's key
In British, Australian, French, and Swiss railway signalling, an Annett's key is a form of trapped-key interlocking that locks levers or other items of signalling apparatus, thereby serving as a portable form of interlocking.[1][2] When not in use, the key is normally held in an Annett's lock that is fixed to the lever or concerned apparatus.[1]
History[]
The Annett's key takes its name from its inventor, J. E. Annett of the London, Brighton and South Coast Railway. Annett patented his design in 1875; in 1881 that patent was bought out by Saxby and Farmer.[3]
See also[]
References[]
- ^ Jump up to: a b "Network Safeworking Rules and Procedures: Annett's Keys" (PDF). ArcInfra.com. Brookfield Rail. 31 March 2016. p. 6. Retrieved 31 August 2021.
- ^ Wägli, Hans G. (2018). Hebel, Riegel und Signale [Levers, Bolts and Signals] (in Swiss German). Diplory Verlag. pp. 159, 176. ISBN 9783033064102.
- ^ Foster, Richard D. (1982). A Pictorial Record of L.N.W.R. Signalling. Oxford Publishing Co. p. 166. ISBN 9780860931478.
Categories:
- Interlocking systems