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How the Railway is Signalled

The Railway comprises a single line between its termini at Chinnor and Princes Risborough, with an additional run-round loop at Thame Junction (just outside Princes Risborough) which for many years served as our terminus there.

The line is operated to 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. Since there is only one of these, he is guaranteed not to meet another driver coming the other way!

The terminus at Princes Risborough has a run-round loop alongside our newly rebuilt Platform 4 as well as a couple of sidings beyond the London end of the station. The commanding 1904 built signal box north of the platform – Princes Risborough North Box – has levers that control the points and disc signals just outside. The levers are normally locked but are released by the single line token being inserted. This is a temporary installation pending full re-signalling once the Independent Line (more later!) is rebuilt.

At Thame Junction there is a simple run-round loop controlled by a ground frame of levers, again released by the token. Though limiting, the ground frame provides a simple system which has served the Railway well through its formative years and still has its uses today if a train can’t proceed all the way into Princes Risborough station for any reason.

The other terminus, at Chinnor, is currently more complex. The points and signals are worked by levers in an even older 1890s built signal cabin (re-located to Chinnor in 2007). Recent track and signalling work there has focused on bringing the run-round loop up to passenger traffic standard (it was formerly only of siding status). This now allows us to run a loco round a passenger train without needing to ask all the passengers to get off every time – particularly welcome for some private charter and evening dining services (when Covid-19 restrictions are lifted).

The signals at each end of the line are mechanically operated semaphore and/or disc signals as once used on the Great Western Railway and the Western Region of British Railways. The equipment was rescued some years ago and has been restored and installed by members of our Signals & Telegraph Department. The signals and signal box at Chinnor give the look and feel of a true GWR branch line station.

The foot crossing of the Railway at Chinnor, which is used by Visitors to access the station, has staff operated gates which are supervised from the signal box and interlocked with the signals for safety. The line has two intermediate vehicular crossings at Wainhill and Horsenden Lane which are also operated by our Volunteer 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 a green flag once the gates have been opened.

There are also several user-worked crossings. At these, it is the road or bridlepath user who is responsible for making sure there are no trains coming, and then working the gates so they can cross. Generally these are found on private roads giving access to a farm or between fields.

The Future

The Railway was extended and commenced services to our new platform at Princes Risborough in August 2018. Our trains travel between Thame Junction and Princes Risborough over a Network Rail siding, requiring much procedural paperwork! Alongside this NR siding lie the remains of the former Chinnor & Watlington line, closed in 1989 and now exposed by clearance of the trees and shrubs which had covered it. The track needs to be totally replaced as the sleepers are rotten and the rails worn. New pointwork is required at both ends. Once done, our trains will use this ‘Independent Line’ instead of the NR siding.

To bring the Independent Line into use we also need to develop the signalling systems at Princes Risborough and that has already started. All the work at the Princes Risborough North Box, restoring and refitting it, and installing all of the signalling equipment beside the line, has been funded by donations to a dedicated appeal. We still need funds in order to continue/complete the signalling works, and to be able to look after and improve the venerable building for the years to come.

If you would like to make a donation to Risborough or Chinnor signal boxes, or any other project on the Railway from your credit or debit card, then please see our donations page. Also, we would always welcome more 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 when the Railway is open.

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