One of only two surviving examples, and to date the only one in running order, it is powered by two AEC 9.6 litre, direct injection 6 cylinder engines through a Wilson epicyclic gearbox. The engines are of very similar specification to those used in London Transport buses for over 50 years. Externally it has been almost completely repanelled and last underwent a complete repaint in 1992/93. More recently it has been completely refurbished internally with new green moquette and trim, returning it to its original GWR appearance. Fully operational, an ongoing programme of mechanical electrical overhaul is gradually proceeding around rostered open days