Editing Railroad switch (section)

=== Facing point lock ===
[[File:Facing points Broomhill.jpg|thumb|left|A set of points on the Strathspey Railway in Scotland. The facing point lock in the middle will need to be withdrawn using the blue lever (behind) on the left before the points themselves can be moved using the black lever (front). Once the points have been moved the lock will be pushed in again with the blue lever to lock the points in position.]]

A ''facing point lock'' (''FPL''), or ''point lock'', is a device which, as the name implies, locks a set of points in position, as well as mechanically proving that they are in the correct position. The ''facing point'' part of the name refers to the fact that they prevent movement of the points during facing moves, where a train could potentially ''split'' the points (end up going down both tracks) if the points were to move underneath the train. During trailing moves, the wheels of a train will force the points into the correct position if they attempt to move, although this may cause considerable damage. This act is known as a "run through".

In the United Kingdom, FPLs were common from an early date, due to laws being passed which forced the provision of FPLs for any routes traveled by passenger trains – it was, and still is, illegal for a passenger train to make a facing move over points without them being locked, either by a point lock, or temporarily clamped in one position or another.<ref>{{cite web |url=http://www.railwaysarchive.co.uk/documents/BoT_Requirements1902.pdf |title=Requirements in Regard to the Opening of Railways |website=RailwaysArchive.co.uk |date=1892 |publisher=British Board of Trade }}</ref>

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