Modified Bulleid WC/BB 'West Country' and 'Battle of Britain' class 4-6-2

Modified Bulleid WC/BB 'West Country' and
'Battle of Britain' class 4-6-2

During the modifying, two major changes occured. First the initial non self balanced crank was recognised to be too weak (one major crank failure occured) and was replaced by a much heavier self balanced crank and this upset the initial balancing. Correspondingly balancing weight should have been removed from the driving wheels. This seems not to have been possible, so the only other option was adding balance weights opposite to the initial position. This should in part explain why the locomotives became heavier.
It has been suggested that: The change from Bulleid chain drive to Walschaerts Valve gear made a significant difference in total weight.
Then there was another major change: in the initial design all three cylinders got their steam through piston valves designed by Bulleid with outside feed, all the movement of pistons of cylinders and valves being almost 120° apart (with a slight correction to compensate for inclination of inside cylinder). This is why all these movements balanced each other out. But the rebuilders changed the inside valve to inside feed which meant that the inside valve worked at 180° from initial position and angle settings were then 60°,60°,240°, (all three on the same side) thus totally upsetting the balancing of the slide valves and attached rods. This created a fore and aft movement of the locomotive. To minimise it proper balance weights had to be fitted to the wheels, but these additionnal weights (and not the previous ones) were responsible for hammerblow (dynamic augment).

An unidentified modified Battle of Britain on the Bournemouth Belle at Eastleigh on 23rd August 1964.

photograph by Ray Soper

34101 Hartland runs through the centre tracks at Raynes Park with a Waterloo to Bournemouth West express formed of Bulleid coaches on 26 September 1964. The platforms at Raynes Park are "staggered" with the up platform on the other side of the station footbridge.

photograph by Keith Harwood

34039 Boscastle and spamcan 34038 Lynton head one way whilst 34016 Bodmin is busy going the other. Interestingly, all three engines are running in reverse gear and two of them live on in preservation. Photographed at Eastleigh on 1st November 1964.

photograph by Ray Soper

34009 Lyme Regis being turned at Oxford. She was there to work the Pines Express that, after being re-routed from the Somerset and Dorset route, always had a Southern pacific to and from Oxford.

photograph by Ray Soper

Another view of 34009 at Oxford, taken on 7th July 1965.

photograph by Ray Soper

An unidentified modified light pacific arriving at Clapham Junction passes an interesting line of vans.

photograph by Ray Soper

Another light pacific photographed at Oxford was this one, Nº 34018 Axminster, on 16th October 1965.

photograph by John Bradbeer

The class prototype, Nº 34001 Exeter is seen here at Weymouth on 21st June 1966.

photograph by Ray Soper

34088 213 Squadron heads a goods working through Clapham Junction during 1966.

photograph by Ray Soper

All photographs are copyright

This page was last updated 10 January 2011