 However, conditions were not always ideal, and the substations were not really designed to cope with regeneration, which meant that often the train switched to rheostatic braking, where the power was dissipated in a resistance bank.The weight of the equipment was also a serious drawback.In the period immediately before the Second World War, there was increasing interest in power-operated gun controls, although military authorities were nervous of introducing a complex system which would have to be maintained in the field.