The UK’s largest surviving Great Western Railway signal box can be found just under an hour from central London, and occasionally, it’s open to the public to have a look inside.
This is the last surviver of two signal boxes that used to control a complex set of junctions at Princes Risborough, on what is now part of Chiltern Railways. Opened in 1904, it closed in 1991 when signalling control for the whole area was shifted to a modern facility based at Marylebone station.
It was nearly demolished but was given listed building status following a campaign, and a newly formed heritage railway, the Chinnor & Princes Risborough Railway was allowed to maintain it.
Unfortunately, works had to stop in 1998 when Railtrack blocked access. A short burst of activity in 2002 when Network Rail took over from Railtrack helped to shore up the building to prevent collapse, but main work didn’t resume until 2013 when staff changes at Network Rail saw more enlightened people in charge.
Access restored, they spent the first couple of years undoing decades of neglect, but there has always been a bigger plan.
Considering that the heritage railway is called the Chinnor & Princes Risborough Railway, it didn’t actually call at Princes Risborough, but this was to change in 2016.
When it was formed back in 1991, the railway was able to run a service along a stretch of closed railway from Chinnor to about a stop about a mile from Princes Risborough. In 2013, a temporary connection was made to allow special trips, but in 2016, the buffers were formally removed and a permanent connection made between Chinnor and Princes Risborough station, which in turn gained a new Platform 4 for the heritage railway in 2018.
But back to the signal box — the plan is to restore all the old signalling for the railway, and operate them from part of the signal box, and works to do that are underway at the moment.
That will take up about a third of the signal box space, so the rest will — planning permissions and funding permitting — be opened to the public on a regular basis so that anyone can go inside, see the signals at work through a glass window, and have a play themselves with a simulated railway connected to the remaining signal levers.
That’s some way off, and to drum up awareness in between restoration works, they hold a few open days — more were planned this year until you know what intervened.
Getting to the signal box means walking past the “no one shall pass” sign, down a long gravel path and then up the steep staircase to get to the control room. Signal boxes have this distinctive appearance in part to give the controllers a good view of the railway, but also because hidden below is the huge interlocking mechanism that turns pulls and pushes of levers above into movements of switches and semaphores on the railway.
A small section of levers has already been connected to the heritage railway on an interim basis, while a live feed from Network Rail has been connected to the bells that would normally tell signalmen what to do.
It has that very distinctive appearance of the signal box, a sight that’s slowly fading from the railways as computer systems take over. But here, physical action is translated into control over the railway.
A lot of work needs to be done to turn this into a visitor attraction, but it’s still a fascinating place to visit, to know that for nearly a century, there was a constant watch kept up here ensuring that trains could go where they should when they should and that nothing would ever go wrong.
Tea and coffee are on offer, and a small collection of souvenirs help to raise money to keep the restoration work chugging along. Your correspondent added to his collection of cups.
Peering outside, modern trains rushed past the signal box, and a white pole standing proud is the first of several that will soon carry old semaphores once more for the heritage railway.
At the moment, while the heritage railway controls most of the tracks, the final mile to Princes Risborough is still Network Rail controlled railway. That has the slightly amusing situation that the signals are still controlled from Marylebone, so they have to regularly phone down the line to get permission to move their own trains. Also, Network Rail rules apply, so those carriages with on-train toilets can’t use them over the final stretch as they are old loos that rather icky dump their contents on the track, and Network Rail understandably doesn’t want that anymore.
There is an application in process at the moment for the heritage railway to take formal control of the entire line.
It’s a slow process to restore a signal box for a heritage railway. Funding and volunteer time aside, the huge interlocking mechanism that controls the signals can be best described as a gigantic Victorian computer, and there aren’t many people who can restore them.
But slowly, step by step, work progresses, and one day, a visit to Princes Risborough will offer a chance to climb up to the signal box, to see how it all works, play a bit at being a signal operator – then catch a steam train to Chinnor.
But that’s for the future.
The Princes Risborough North Signal Box probably won’t have any more open days this year, but you can sign up to their newsletter to find out when the next one takes place.