The Friends of the
National Railway Museum

South of England Group
Vice Presidents: Richard Hardy; Sir William McAlpine Bt, FRSE, FCIT, FRSA

Last Update

Talk Synopsis

5 January 2006

Operating or wrecking the National Collection
Richard Gibbon
12 May 2003

To preserve a rusty heap, or to enable people to appreciate how railways operated in the past? This was the tricky question handled by Richard Gibbon at our May meeting. Many in the museum profession see it essential that the patina of age is retained, but Richard felt that if the public were to properly appreciate the vehicles preserved at the NRM, they must be able to see them in their operating state. This brings complications in that the museum environment is different from that it experienced in service as was illustrated with pictures of the superheater elements on the Duchess. In service, wear was due to erosion by ash, but in preservation corrosive condensation within the tubes was a much greater problem.

Wherever possible, the museum will retain the original material, in some cases calling for ingenious repair methods when replacement was the obvious solution. Here the role of the museum and a preservation railway differs. Where replacement was the only solution, the museum would retain the replaced part. Hence, when the side sheets of the Duchesses' tender were replaced to meet current loading gauge limits, an original was retained with its scuff marks caused by the streamlined casing.

Pete Waterman had agreed that the restoration of the Super D used the original design practices. In a couple of instances these had required the re-learning of old skills. In accordance with LNWR practice, the bottom of the tender was made up of a large number of small plates - reputedly, the off cuts from the plate shop. Riveting together 2 plates has no fears, 3 can be tricky, but having four plates meet at one spot is nearly impossible. Eventually, by relearning old practices the museum had succeeded. A more interesting case was that of brazing the copper cuffs onto the ends of the superheater flues. Every attempt failed as the molten metal dripped out, until that is the tubes were hung vertically! There is no record that Crewe brazed the cuffs on with the tubes vertical, but it did look as though the museum had discovered how they had done it.

This brought Richard onto the subject of skill retention. At present, the museum was able to draw upon a pool of engineers who had served their time in heavy engineering. However, changed education practices meant that there were many fewer coming into engineering by this route. As an attempt to retain the skill base, efforts were in hand to enable the museum to take on 2 apprentices. This would go some way to preserving skills from the steam railway. However, the expertise for building large locomotive boilers has already gone and Richard could see the time when all the present mainline locomotives were stopped because their boilers were no longer steamable, and repair was impossible.

Safety regulations inevitably move forward as our experience grows. However, attempting to apply modern standards to heritage vehicles or structures can be a nightmare and had caused Richard many sleepless nights. An example of this was the foot bridge from Percy Main which is prominently displayed in the Main Hall. Before the public could be allowed to cross it, it had to be subject to a proof test. In accordance with current regulations, this proved to be the equivalent of 500 people. We were left to consider on our next visit to the museum whether it was possible to get anything like that number on the bridge at any one time!

After a lively discussion period, Richard closed with an explanation for the missing 3rd beat on the Super D. At some time the frames became bowed, moving the pivot on the weigh shaft upwards. On many locomotives this might not be significant, but the Super D used Joy valve gear which relies upon the upward movement of the connecting rod. A previous experiment on 2 members of the class had shown that 3rd beat could be restored by mounting the shaft in modified bearings. Would the museum allow a similar experiment on 9395?

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