I read with interest the possibility of double deck railway carriages as a way of increasing capacity on British railways (NCE 30 June).
What seems to be have been overlooked is that British Railways once built and operated two 'doubledeck' trains, and the reasons why more were not built and operated is still very pertinent.
After the Second World War, Southern Railway's (SR) innovative chief mechanical engineer, Oliver Bullied, had his staff produce a design for a four car 'double-deck' electrical multiple unit train for the electrified suburban lines.
Two of these trains were introduced into the renamed Southern Region in November 1949.
Trials showed that while they could in theory carry 40% more people than a normal eight car train, they took much longer to load and unload. The reason for the delay was limited space. The loading gauge had insufficient height to allow for two completely separate decks so upper compartments had to be interlaced, and access was via the lower compartment as there was insufficient height for a corridor on both levels.
This problem of loading gauge restrictions is as true today and it is difficult to see how double deck trains could be made to operate in the UK.
Deryk Simpson(M), 6 Upper Broom Way, Westhoughton, Bolton BL5 3YG