1840s block signalling system:
The block system of signalling was introduced in the 1840s so that only one train could occupy a section of track (a ‘block’) at any one time.
The indicators which showed signal positions and whether a train was in the block were connected by telegraph wires to adjacent signal boxes in either direction.
The principle of the system is still in use today, although much improved, and is still the basis of many modern, high-speed railways. This example was used in Bagshot, Surrey, and was generously donated by Steve Sharp.






