Chair (railway)

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Chairs, in UK railway parlance, are cast-iron items screwed or bolted to sleepers and used to support bullhead rails. The rail sits in the chair and is held in place by a wooden, or sprung metal, key.

Most main lines in the UK are now laid with flat-bottom rail, which does not require chairs, but chaired track can still be seen in sidings.

The London Underground still uses chaired track because it allows for rapid replacement of damaged rails. The old rail can be released quickly by knocking out the keys with a keying hammer.