In 1933, the Great Western Railway introduced the first of what was to become a very successful series of railcars, which survived in regular use into the 1960s, when they were replaced with the new British Rail "first generation" type diesel multiple units. The original design featured 'air-smoothed' bodywork, which was very much the fashion at the time. The rounded lines of the first examples built led to their nickname: "flying banana". The preserved railcar #4 is an example of the original, rounded body shape. Later examples had much more angular (and practical) bodywork, yet the nickname persisted for these too. (source Wikipedia).
