 Later the "Castle" class steam locomotives and, from 1959, "Warship" class diesel-hydraulic locomotives were used.The service was suspended during World War 2, and it was not until 1954 that the 105-minute schedule was again achieved.During this time "The Bristolian" became one of the few named trains to be scheduled for haulage by a gas turbine locomotive when, between April and May 1952 it was scheduled for haulage by 18100, the Metropolitan-Vickers experimental locomotive; but otherwise the mid 1950s was a time of very fast running under steam haulage, the intention being to reduce the regular schedule below 100 minutes.