In this guest post, Bob Gwynne, Associate Curator at the National Railway Museum, takes a look behind the scenes at some essential conservation work.
When the National Railway Museum expanded into York’s former diesel depot and created The Works, it developed a number of new approaches and displays that helped it win the prestigious European Museum of the Year award in 2001. These included a workshop, balcony viewing area and The Warehouse, the country’s first museum store open to the public seven days a week.
On the Works Balcony there was space to put signalling centre stage for the first time, with a direct link to the York IECC (the main signal control centre for York) as well as a demonstration known as NRM Central, a mock-up of a signal box complete with a real Midland Railway tumbler lever frame. The lever frame and instruments were linked to a computer, allowing the frame to be worked in a way that demonstrated how a train would be signalled past a signal box on the ‘big railway’.
However, it soon turned out that the sequence, which was carefully accurate, took longer than many people were prepared to wait. Even those happy to give it a go found themselves interrupted as others tried to operate levers that could not be moved out of sequence – as in real life. This wore parts on the lever frame and so the decision was taken to leave the demonstration open to view, but behind a small fence to remove the temptation to pull on levers. Today NRM Central is part of the monthly set of demonstrations delivered by our skilled Lancashire and Yorkshire Signalling School volunteers. On the second Saturday of every month, interested visitors can have a go at working NRM Central and learn more about how signal boxes and signalmen and women ensure that trains runs safely. Instruction is given by volunteers who are highly knowledgeable about the way a signal box safely signals trains and a certificate is awarded to all who stay the course.
Unfortunately, when NRM Central was on open display it suffered some damage from visitors who had hung on the levers or held children up to have a go. Some parts were worn to the point where our L&Y volunteers knew there were certain movements possible with the frame that should not have been – and which would have been instantly reported and quickly fixed had they been out on the real railway. However, fixing a signal box mechanism is something that skilled signalmen never do, a division of responsibilities which exists for good reason.
Enter, then, our good friends the Network Rail locking team, who were interested in refurbishing the lever frame so that it worked correctly as a training exercise. The fact that the frame was in a warm, dry and very accessible location, with a good café close by, was naturally a bonus.
In December 2016, when the museum is at its quietest, the team descended on York from the four points of the compass to work on refurbishing and repairing the core of NRM Central. They swiftly discovered that the 12 levers had not had maintenance prior to being fitted in the museum display, and located the wear that needed repair. They also quickly noted that there ought to have been at least two more levers for the track layout as it was displayed, particularly given the crossover connecting the two lines on the signal diagram.
The frame had been selected while The Works was under development because the locking – the means by which you can only move the levers in the correct sequence – is above the floor and behind the levers on a Midland ‘tumbler’ frame, rather than in a separate floor below the levers. Putting the locking in a separate space below the main signalling floor is a useful way of separating out responsibilities and the approach to maintenance. This of course gives signal boxes their traditional appearance as two storey buildings, but would not work in a first floor gallery display.
The Network Rail locking team were happy to repair NRM Central as it was, but told us that had it been one of their projects, there would have been serious work to make it absolutely fit for purpose. Their encyclopaedic knowledge of mechanical signalling meant they had encountered the rare form of lever frame fitted to NRM Central before, and knew of examples still in use on the routes once run by the Midland Railway.
Eventually they were able to sign off the frame as repaired, but only after the head of the section had tested their work himself. Thanks to the team, NRM Central is now up and running with no incorrect moves possible. The invitation has been extended for the team to come and test their knowledge of signalling operations sometime on the antique (but accurate in every detail) model that is the L&Y Signalling school.
Today the UK has over 400 mechanical signal boxes, and the locking team encounters many different issues as they travel the country making sure these essential parts of the rail infrastructure continue to deliver a safe railway. The long-term plan is to centralise control of railway signalling into just 12 rail operating centres (ROCs), but this work will not be completed in the near future. In the meantime, the locking team keeps the country’s aged – but tried, tested and very robust – mechanical signalling system going.
If you would like to see the L&Y Signalling School in action, you can find further information here.