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Princes Risborough North Signal Box

This page will give the reader an insight into the history of the largest remaining Great Western design signal box in the country, from its construction in 1904, closure in 1991 and the dereliction that followed, through to again becoming a working signal box controlling the passage of steam trains.

The image above shows a computer simulation of what we hope the box will look like when the renovations are complete. Currently only partly restored, the signal box already has a small set of working levers which control the points and signals on the Chinnor & Princes Risborough heritage steam railway to the rear of the box which runs parallel to the Chiltern main lines at the front of the box. Further restoration work continues.

The signal box stands just to the north of Princes Risborough station which is served by mainline Chiltern Railways trains as well as the Chinnor & Princes Risborough heritage railway. Frequent mainline trains call at Princes Risborough from Birmingham (Snow Hill), Birmingham (Moor St), Oxford, Banbury, Aylesbury, High Wycombe, Beaconsfield, Wembley and London (Marylebone).

The signal box is not routinely open to the public but we do have Open Days during the course of the year, which dates will be advised on this website.

The Early Years

The first railway to reach Princes Risborough was the Wycombe Railway on 1 August 1862, which saw the extension of its single track line from High Wycombe run all the way to Thame as part of its planned Oxford extension. Parliamentary approval had been granted little over 12 months previously on 28 June 1861.

Next came another branch built by the Wycombe Railway, this time to Aylesbury which opened on 1 October 1863. Following that less than a decade later came the Watlington and Princes Risborough Railway in 1872. It connected the Oxfordshire towns of Watlington and Chinnor to the main GWR network at Princes Risborough.

The Princes Risborough North signal box you see today was built in 1904/5 as part of the Great Western and Great Central Joint Railway's 'Bicester cut off' route between Princes Risborough (then on the Wycombe Railway route from High Wycombe via Thame to Oxford) and Aynho (on the Oxford – Banbury line) - see the red line on the map.

This completed the GWR's 'North Main Line' from Paddington to Birmingham and on to Liverpool and Birkenhead. Previously trains had to be routed via Oxford.

This was not the first signal box to be built at Princes Risborough. There is reference to a Wycombe Railway signal box (and station) dating back to 1892 for their line to Oxford. The North Box was not alone: a smaller Princes Risborough South signal box stood on the London side of the station on the other side of the line in what is now the station car park. The South Box closed in 1968 and was demolished.

The task of the North box was to control the junctions between the double track main line and the three single track branches: to Aylesbury; to Watlington (via Chinnor); and to Oxford (via Thame). Without knowing the history of the area it would be easy to think the two lines that leave the station in a northwest direction around the left curve are one for the ‘Up*’ line and one for the ‘Down*’. They were actually each single, bi-directional lines, the left hand going off via Chinnor, the other via Thame.

*Railways historically only go in two directions, Up or Down! The Up direction refers to lines going towards London, the Down being in the opposite direction.

The station itself was a classic GWR design station building which cost £1104 9s 5d to build and additional general costs of £824 8s 0d. It had two through platforms facing loop lines on the outside of two centre fast roads. Both through platforms had North facing bays on the back, and both bay roads had engine release loops. The loops were necessary so that the same single locomotive could detach from the train it had just pulled in to the platform and then run round on the parallel passing loop to rejoin at what would now be the front of the train. If the passing loops are included, Risborough was eight tracks wide with four platform faces!

One of those eight tracks was a freight by-pass line on the West (down) side out of shot on the left in this more recent picture above (looking North). Princes Risborough North box can be seen in the distance near the top of the picture as can the multiple semaphore signals it controlled. The left hand station canopy hides the Watlington branch line and bay platform. Note the single carriage behind loco 5420 on the left.

The Box Working Life

The lever frame installed was the GWR standard of the time, a 'double twist' frame, so called because it describes the action of the interlocking components. It was sized for 125 levers, which determined the size of the building. 97 were actually fitted, though there may have been alterations over the years. There would have been very little electrical equipment: probably just the bell telegraph to adjacent signal boxes and some indicators for signals too far away for the signalman to see. They would have depended on batteries for their operation.

Mains electricity was not common, and wasn't provided to the North box. It would have been lit by oil lamps, and probably did not have mains water. There were water butts at each corner collecting rainwater from the roof, which would have been used for cleaning and perhaps topping up batteries. Drinking water would have been carried from the station, which had a borehole. The loo was a 'thunderbox' style earth closet, housed behind one of the outside doors by the staircase at ground level. Heating was of course by coal, using two fireplaces. Different types of stoves have been fitted over the years, but the box was reputedly always difficult to keep warm.

At some stage a gas supply was provided and gas lighting installed. The original installation, with a few alterations, lasted over 50 years. In 1958, now nationalised under British Railways, the box got a thorough refit and a new lever frame, still of 125 levers in size. This was of the state-of-the-art “5-bar vertical tappet” design, and because its levers were closer together it was shorter than its predecessor. Much greater use would by then have been made of electrical equipment for track circuits and other signalling equipment. It is likely that mains power would have been provided by then along with the luxury of electric lighting.

Other changes were made. We don't know exactly when, some may have happened at the time of the 1958 refit, some earlier: a flush toilet was provided in a new booth on the operating floor; the staircase was replaced (probably due to condition); running water was provided; floor standing staff instruments for the single lines were replaced by Tyers key token instruments on cupboards.

Unfortunately the new installation was not to perform in its 1958 form for long. In 1967 the route was downgraded and express services from Paddington to Birmingham and beyond ceased. In 1968 the line from Princes Risborough to Aynho was singled, with just a two hourly DMU service running through. Many other signal boxes on the line were closed progressively.

The track layout at Princes Risborough was simplified, and the Down platform was closed and its buildings demolished. All trains used the Up platform or the Aylesbury bay. Eventually the footbridge was demolished, and the Down platform site became a ballast storage area. Signals added for the layout changes were colour lights, worked from circuit controllers (switches) on the levers. Inside the box, the lever frame was shortened to 70 levers, and the operating floor was partitioned. The signalling was now worked from the north end, the south serving as an office and later a crew mess room. The control panel seen on the left of the picture was added to remotely work the crossing loop at Bicester, when the local signal box there closed.

Around this time, a ladder appeared on the north end of the box to serve as a fire exit for any signalman faced with the choice of scorching or leaving via the window. The coal stoves were still in place, but some electric heaters were installed too.

There were minor changes and additions subsequently, as is common, and there was building refurbishment (a repaint) around 1976 but things stayed much the same until the “Route Modernisation” of the 1980's came along. Despite starting the decade with proposals to close the line north of Risborough, to shut Marylebone and to route any vestigial passenger traffic into Paddington, the line was progressively upgraded. All semaphore signalling was replaced with modern colour lights working from Solid State Interlocking and an Integrated Electronic Control Centre at Marylebone. February 1991 saw the last train signalled from Princes Risborough North box, and the redundancy of its last resident signalmen. The era of mechanical signal boxes was drawing to a close.

Closure & Dereliction

British Rail closed the signal box in February 1991, when a new “Integrated Electronic Control Centre” at Marylebone took over, as part of the upgade of the line. When the closure was announced local people successfully campaigned to get the building preserved, and it was duly “listed” Grade 2. However there was no apparent use or occupier for the building.

Around the same time, the Chinnor & Princes Risborough Railway Association (C&PRRA) had been formed, and purchased track between Chinnor and the British Rail boundary on the outskirts of Princes Risborough. It was hoped to soon be able to negotiate land or running rights with BR to allow heritage trains to run into Princes Risborough station using a restored Watlington platform. It was clearly sensible that the Princes Risborough North signal box should pass to the C&PRRA at the same time.

BR granted interim access to the box by C&PRRA members, who would look after it and restore equipment etc. A lot of work was done: the roof was repaired and a chimney rebuilt; the staircase was repaired and strengthened; a full repaint was carried out inside and out; equipment was bought from other closing boxes to replace missing items in the North Box. The building was generally maintained in readiness for the surely not too distant day when it would come back into use… in the early nineties!

Negotiations dragged on and meanwhile rail privatisation and health and safety came along. In 1998 a decision was made that it was no longer tenable for C&PRRA members to routinely access the box. Maintenance and restoration stopped. Vandals seized the opportunity and broke 197 of the 421 window panes. The pigeons were pleased, and moved in.

By the early noughties, the place was in a sorry state. Prior to some track relaying work, the box was considered a safety hazard due to the potential for broken glass to fall on workers below. The decision was taken by Railtrack (or was it Network Rail by then?) to board up the box and remove the stairs. The building, if not its fate, was sealed.

In 2011 there was a break-in. The police and Network Rail provided escorts so C&PRRA could access the building. It revealed an alarming state of affairs: a long term water leak had flooded part of the top floor, flowing down through the building beneath. The ceiling of an equipment room had collapsed as a result. Equipment was rusted and in some cases full of water. One of the main structural timbers had rotted out and the brickwork showed numerous cracks indicating some movement of the structure. The arch over one of the windows had collapsed and the full extent of the pigeons' droppings was recognised for the first time!

Clearly something had to be done, and Network Rail agreed to provide an escort occasionally so we could take remedial action, but with perhaps one day of access a month and no funding we were very limited. None the less, work had restarted and progress had been made for the first time in 13 years of dereliction!

…(Back to) The Future

As recently as 2012 the signal box was on the edge of being declared unsafe and a threat to the very railway it had been built to protect. Had it been deemed so, then all traces of it would have been long gone by now, irrespective of it being Grade II listed. Now we have turned the corner and the box is once again structurally sound and its condition improving with every passing weekend, we need not only to have regard for the past but also to look to the future.

Our aim from the very beginning was to restore the building to its former glory and get the signalling equipment working, to be able to use it both operationally to control trains on the Chinnor & Princes Risborough Railway and also to open it to visitors as an example of our railway heritage. Our plan is to restore the signal box to its post-1958 condition.

Why 1958?  It was that year when British Railways carried out a full refit of the box which included installing the lever frame that is still there today and some of the other kit from that time survives. Availability of authentic British Railways signalling equipment pre 1958 is virtually non-existant (or certainly not at prices we could hope to afford). Another important factor was that by 1958 the thunderbox toilet had demised and the inside loo had been installed!

Future pages will set out our aims and ambitions in the two areas of signalling and demonstrations. We have no rigid timeframe and whether some of the longer term ideas come to fruition is uncertain as external factors can and do change, resulting in many plans needing to be revised. The rather turbulent year of 2020 was a very good example of this.

Our signal box serves the Chinnor & Princes Risborough Railway and its heritage train operations. From its humble start over 3 decades ago, the railway is still growing and its plans have a direct bearing on not only what equipment we install in the box but also on the resources and manpower available. The latter two are of course the two main shortages on any volunteer run, charitable organisation and ours is no exception so if you haven’t already, please visit our donations page if you can help this wonderful piece of railway history have a more secure future. Thank you.

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