Coupling code: Red Triangle
Underframe: 57ft 6in
Engines: Leyland 125hp
The UK's first proper DMUs. The sets met with huge success, starting a trend of greatly increasing passenger figures which most first generation DMUs continued.
The were used in the West Riding on Leeds - Bradford services, introduced in June 1954, and were allocated to Bradford Hammerton Street depot.
Just eight power-twin sets were built with 125hp Leyland engines and hydraulic transmission. There were over 200 more 79xxx Derby Lightweight vehicles built powered by 150hp AEC engines and mechanical transmission. The control systems also differed, when codes were introduced these sets became Red Triangle coupling code, the others Yellow Diamond. Had they survived long enough to be given class numbers the two types would have gained separate numbers, and so are treated separately here.
The different engines and control system meant these sets were non-standard and destined for early withdrawal, they were withdrawn in early 1964, just less than ten years old.