In the 1860s, Charles Pearson had the idea to link up some of the capital's mainline stations with a new underground railway - the birth of the so-called Tube. As well as recalling its construction, this programme also recounts the tale of a bus that played a vital part in the First World War. The B-Type - a common sight on the streets of the capital before the war - worked as troop carriers on the front line in France. Also recalled is Hannah Dadds, who in 1978 became a trailblazer for women as she stepped into the cab of a District Line train to become the first ever female Tube driver on London Transport.