Black Prince – the remaining work
article by: Ian Crowder
Updated August 2009:
Black Prince - David Shepherd's 9F class heavy freight
locomotive no. 92203 - is was rededicated on Monday 18 October 2004
at Toddington. However, the locomotive ran just one trip from
Winchcombe to Toddington. The other services were hauled by Great
Western heavy freight tank locomotive no. 4247, built in 1916 -
more than four decades older than Black Prince.
Here are a few questions and answers published on this website
about Black Prince and its return to steam, at that time.
Why is Black Prince only running one
trip?
Although it has just undergone the first major overhaul since it
was built in 1959, some work still has to be completed. After
taking professional advice, it has been decided to run the
locomotive as little as possible until this work can be done.
Why are you taking such care?
The main task remaining is to fit new tyres to the rear set of
driving wheels because the flanges, which guide the locomotive
along the line and round curves, are worn. The tyres, which include
the flanges, are made of special steel and are separately fitted to
the wheels. There is some work remaining on the boiler as well.
Why should just the rear driving wheels
become worn?
Black Prince, like other tender locomotives, is designed to travel
mainly in the forward direction. The locomotive was withdrawn from
service on British Railways in 1968 and, since then, it has worked
almost entirely on heritage railways such as the Gloucestershire
Warwickshire Railway. This means that in the absence of turntables
the engine must run in reverse as much as it runs forward. When
running in reverse, the rear driving wheels take the brunt of wear
when the locomotive is negotiating curves. The sharper the curve,
the greater the wear. There isn't this problem when running
forwards because the leading 'pony' wheels are designed to help the
locomotive negotiate curves. Black Prince has run up several
thousand miles on heritage lines - half of it in reverse.
Why are worn flanges a problem?
Because if they wear beyond a certain amount, there is a very
remote possibility that the rear driving wheels could lift against
the rail, which could damage both the rear wheels and the track. We
feel that it is better to be absolutely safe and avoid this
possibility completely. David Shepherd is aware of the
problem and agrees that this is the best option.
How will Black Prince get to
Winchcombe?
It will run 'light engine' - that is, without any coaches - in the
reverse direction. We can do this in complete safety by avoiding
sharp curves and taking the journey gently. There is no problem
with the locomotive running forwards.
If you can do that, why couldn't you take the
engine to Cheltenham Race course - we would have got a longer ride
then.
Until our signalling is operational at Cheltenham (expected
by March next year) we cannot have two separate train or locomotive
movements at the same time beyond Winchcombe.
What happens to Black Prince next?
It is likely that the rear wheel set (the two wheels
complete with the axle) will be removed at Toddington and then
taken away for the specialist re-tyring work to be done. Another
possibility is that the engine is taken away complete to a
specialist contractor (NOTE: In fact the latter happened - the
locomotive was taken to Ian Riley's Bury, Lancashire works for
retyring. The engine was returned 'ready to run').
How long will the work take?
That is difficult to estimate with accuracy because the old tyres
must be removed and new ones manufactured specially to fit the
wheels. Tyre manufacture and fitting is a highly specialised job.
Once fitted (by heating the tyre to a very high temperature so it
expands and can be slipped on to the wheel; the tyre is then cooled
so it shrinks on to the wheel) it must be machined to the correct
profile. We believe that at the earliest, the locomotive will be
back in working order in about April or May.
Isn't this a blow for David Shepherd and for
the GWR?
Yes, it is. Although the wear was known about before it left
the GWR for overhaul, it was not possible to get the work done
ahead of its return to steam.
Hasn't the locomotive already run up some
mileage on another railway, running in before it came back to the
GWR?
Yes, it has. However, we don't believe the degree of wear was fully
appreciated while it was running-in and, already being worn, the
rate of wear has probably accelerated. We feel that to be
absolutely certain it is best to replace the tyres that have the
worn flanges.
How long will the new tyres last?
Replacing all of the tyres (all 10 of them!) will give the
locomotive a new lease of life. The present tyres, we
believe, were those fitted when new so the new ones can be expected
to last for several decades.