Class 31 Engine Identity Plate 'Mirrlees' stamped with the number 485117. Serious problems were experienced with the original Mirrlees power units and from 1964 the decision was made to re-engine the entire class with English Electric power units rated similar to those fitted to the English Electric Type 3s (Class 37). The first example to be re-engined was D5677. Also with this lot, an alloy English Electric Plate, removed from D318 after secondment for filming duties for the Great Train Robbery film 'Robbery' in 1967, now of course preserved at Tyseley.