Signalling Now

How the Chinnor and Princes Risborough Railway is Signalled.

The CPRR comprises a single line with two termini. It operates a version of traditional "One Engine in Steam" (OES) signalling 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.

Thame Junction, the remote terminus, comprises a simple run-round loop and a single siding. Connections are worked from a ground frame of levers which are normally locked but can be released by the token. Train movements are controlled by a combination of “Stop” boards and handsignals.

The other terminus, at Chinnor, was until recently also controlled by a ground frame though its layout and operation is more complex. The points and signals are now worked by levers in a century old signal cabin re-erected in 2007 which is still being developed, but the vestiges of the old ground frame interlocking and operating principles are still present: those which provide routes towards the single line are still released by the token.

Though limiting, the token released ground frame provided a simple system which served the CPRR 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. 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. Also we cannot run around a train at Chinnor with the passengers still aboard (as the Loop is beyond the end of the authorised passenger running line), so we have to “top and tail” dining trains etc. in order to avoid throwing passengers out in the rain between courses!

In due course it is intended to relocate one set of points, and then with the addition of a few more signals to remove this token interlock (the necessary protection of movements in the station area then being provided through the signals alone). This will allow much more flexibility in the Railway’s operations.

Signals at Chinnor are mechanically operated semaphore and disc signals as once used on the Great Western Railway and the Western region of British Railways. Equipment was rescued some years ago, and has been restored and installed by members of the CPRR Signal and Telegraph Department.

The line’s two intermediate vehicular crossings at Wainhill and Horsenden Lane are also operated by railway staff, and stand normally with their gates closed across the line. Depending on the timetable and the numbers of staff (all volunteers) available, the crossings may be worked by train crew or by a keeper based at the crossing. Each crossing is protected by “Stop” boards, and authority for trains to pass these is given by handsignal once the gates have been opened.

The foot crossing at Chinnor used by passengers to access the station has staff operated gates which are supervised from the signal box and interlocked with the signals.

There are also several user worked crossings. At these, it is the road or bridlepath user’s responsibility to make sure there are no trains coming, and then to work the gates so they can cross. Generally these are found on private roads giving access to a farm or between fields etc.

As the railway grows, and particularly with its extension into princes Risborough in mind, we must prepare for it's future operating requirements. It is for this reason that the Chinnor signal box was commissioned in September 2008 and the installation of signalling at Chinnor is being progressed.

Help!

The signal box relocation, building works and restoration were costed out when the box was offered to the CPRRA. Of course the offer was not predicted, and the Association budget could not afford to fund the whole project. We had to find another way, so an appeal was launched. It quickly reached a level where we could be confident of saving and moving the cabin, but the appeal is still open as we want to be able to fund its restoration to full use complete with all the external equipment.

Also, we are always short of working volunteers. If you would like to be a part of this project by joining the team please get in touch. You can use the feedback section of this website, or simply come and see us at Chinnor.