clip and scotch
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To clip and scotch a set of railway points (Amer. a ''switch'') uses two pieces of equipment to temporarily lock a set of points into a particular position. The ''point clip'' clamps the end of a moving rail (the switch rail) of a set of points to its associated stock rail, and the ''scotch'' is a timber wedge used to ensure that the other moving rail is kept away from its associated stock rail. In this way the points are fixed in either the 'normal' or 'reverse' positions and cannot be moved by the usual setting mechanisms. For infrequently used points, this guards against mechanical failure of the points leaving them in a condition to derail trains. The 'clip and scotch' method can also be used to positively deny access to the turnout or mainline.


Scotch block

A 'scotch block' is not used, as this is a different piece of equipment clamped to a rail used to ensure that stationary railway vehicles do not move, with much the same function as
chocks Chock or Chocks may refer to: Devices for preventing movement * Wheel chock, tool to prevent accidental movement * Chock (climbing), anchor * Chock, component of a sailing block Other uses * Chock (surname) * ''Chock'' (TV series), a Swedi ...
used to keep aircraft stationary.


Spike and wedge

In North America the term Spike and Wedge is used as instead of a clip, a
rail spike A rail fastening system is a means of fixing rails to railroad ties (North America) or sleepers (British Isles, Australasia, and Africa). The terms ''rail anchors'', ''tie plates'', ''chairs'' and ''track fasteners'' are used to refer to parts ...
is driven through a hole set in the metal base plate that is located flush up against the switch rail, holding it in place against the stock rail. The block of wood set in the open gap is known as the wedge and is functionally equivalent to a scotch.


References

* (NOTE: Document not found/no longer available as at 12-Feb-2018) * Permanent way {{rail-transport-stub