British Rail class 71

The class 71, initially known as the type HA, was a locomotive for third rail electrified lines. Depending on the region, they were operated with 650 or 750 volts. For station areas with many points, in which there was an overhead line instead of the third rail, they had a pantograph on the center roof. To overcome short non-electrified gaps, they had a flywheel to maintain speed. Nevertheless, the first ten locomotives were converted to diesel locomotives as early as the 1960s because they had competition from the class 73 electro-diesel locomotives. The latter ultimately led to all remaining locomotives being withdrawn at the same time in 1977.