Vertical ride testing of APT-pop train with enlarged (110 litre) surge reservoirs (IM-DOS-040)

One of the experiments performed with POP train during R & DP test track running in Sept/Oct/Nov. 1976 was to establish the effect on vertical ride, with particular reference to the transmission of H3x bogie pitch, of replacing the 80-litre airspring surge reservoirs with ones of 110-litres per spring.