How the Chinnor and Princes Risborough Railway is Signalled.

It isn't! At least not in the obvious sense. Yet.

The CPRR operates a version of traditional "One Engine in Steam" (OES) regulations. No train may occupy the single line unless its driver has what we call the "token" (which is a bit like a giant engraved key) as his authority.

There are a number of fixed "Stop" boards on the line, protecting crossings and points etc.. drivers are authorised to pass these by handsignals from crossing keepers or shunters on the ground.

The points at Chinnor are worked from levers (known as a "ground frame") in a small hut, and are locked normal and can only be released using the token. No other loco or train may enter Chinnor station or leave the yard while the service train is out with the token.

At the other end of the line, Thame Junction, there is a loop which enables the loco to run round to the other end of its train. Again, the points are worked by levers which are normally locked. They can only be released using the token when the train gets there.

Though limiting, this is a simple system which has served the Railway well through its formative years. The chief limitation is that nothing can move at Chinnor station while a train is out on the single line with the token, so we cannot shunt or prepare the next train until the first gets back.

If we believe the Railway will (must) grow, we must plan for the future. It is for this reason that the Chinnor signal box project is being pursued.