Point machine

From Wikipedia, the free encyclopedia

A points machine is a device for operating railway turnouts especially at a distance.

[edit] Overview

In the earliest times, railway turnouts were operated manually by simple levers. There are a number of different kinds of levers including throwover levers which stay in the last position thrown, and ball levers which revert to a standard position.

Gradually the turnouts on main lines came to be operated at distances up to about 300m by centralised levers in signal boxes.

Since the limitation of mechanical operation restricted the design of track layouts on the one hand, and tended to require more signal boxes, even lightly used ones, on the other hand, there has always been a desire of railway administrations to increase the distance that remote turnouts can be operated. This requires some kind of power operation of points and signals. The principal means of power operation include hydraulic, pneumatic and electric.