Airfix Class 31 / Athearn PA-1 Loco chassis
An instant improvment on the 1970s bogie-mounted worm-and-wheel motor. I recall there wasn't even a central axle on the design.
PA-1 Were 2000hp locos made 1946-53
BR Class 31 were 1470hp locos built 1957-62
Both A1A-A1A