noun London. Probably rhyming slang for THE SMOKE; used by trainspotters; however, Garth Andrews, a retired deputy head of Records and Archives at the British Railways Board, wrote to this dictionary in May 2003, to suggest that 'this has nothing to do with rhyming slang for "smoke". Old Oak Common was the premier engine shed on the Great Western Railway, providing the motive power for crack expresses out of Paddington. It is, of course, possible that Old Oak Common provided the inspiration for the rhyme – if rhyme it is UK, 1970