B T H and North British Type 1 Bo-Bo Diesel-Electric Locomotives - British Railways Classes 15 and 16

The British Railways ''Pilot Scheme'' orders of 1955 included ten BTH and ten NBL Type 1 locomotives, these being introduced during 1957-61 for use in East London, and on the Great Eastern and London, Tilbury & Southend lines. The BTH fleet subsequently expanded to forty-four, as a consequence of their light axle-loading and the availability of spare manufacturing capacity which BR chose to exploi...