A class 20 Diesel Electric Locomotive. 20137 is privately owned and is a permanent resident on the GWR. 20137 was purchased from British Rail at Wigan in 1994 and moved to the GWR. 20137 was returned to working order in 1995.
- Wheel arrangement: Bo-Bo
- Origin: Built by English Electric at Newton-le-Willows in 1966.
- Engine/power: English Electric 8SVT Mk.II, Turbo-charged, 1000hp at 850rpm. Power equipment by English Electric.
- Length over buffers: 46ft. 9in. (14.25m)
- Working weight: 73.5 tons
- Maximum speed: 60 mph