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. The purpose is to prevent access from sidings to the running line without authority.[1] When not in use, the key is normally held in an Annett's lock that is fixed to the lever or concerned apparatus.[2]
- ^ Wägli, Hans G. (2018). Hebel, Riegel und Signale [Levers, Bolts and Signals] (in Swiss German). Diplory Verlag. pp. 159, 176. ISBN 9783033064102.
- ^ Cite error: The named reference
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