A pioneering diesel railcar service with a buffet commenced running in July 1934 between Birmingham Snow Hill and Cardiff, running non-stop through Stratford, with only two stops at Gloucester and Newport. This was the first long-distance diesel express service in Britain. It proved so successful that larger railcars with more seating and no buffet had to be introduced to cope with demand, and even this had to be augmented by a normal locomotive hauled service. During the Second World War, the railcar service was the only through service using the line, as all other long-distance trains were suspended. At this time it consisted of a three car train consisting of a standard carriage sandwiched between two railcars. Two such trains ran to and from Cardiff daily at this period, and a stop at Stratford was introduced.