 Because the track involved had been formerly operated by the Great Western Railway, the signals were on the right hand side, but the train was hauled by one of the new British Railways Standard Class 7 locomotives, which had its driving position on the left hand side.This incompatibility hampered the driver's view of the signals.There was a berth track circuit approaching the crossover, but it was much longer than the train, which made it hard for the signalman to estimate the speed of the train.