31120 and originally Diesel 5538, was a diesel owned by the Other Railway.
31120 was built by Brush Traction in 1959, and originally carried the number 5538. He/she was later present to take Gordon's passengers at Barrow-in-Furness, after his fiery experience when a puncture dampened Gordon's fire and narrowly avoided overheating. 31120 was later retired from service in August 1991, and scrapped three years later.
31120 is based on a BR Class 31, hence his/her number. D701 is another member of this class. Around 26 locomotives had been purchased and preserved for use on many heritage railways around the UK.
31120 was painted in the British Railways' Rail Blue with yellow warning panels but later was painted in Railfreight Grey with yellow cabs in he/her working life
- 31120's headcode is "1X01", which is odd, as the "X" indicates "Royal Train" or "out-of-gauge load".
- Over 263 of this class was built from 1957 and 1962, 26 of these Diesel engines survived into preservation.
- Ten more of these engines were in preservation but were scrapped from either accidents or to give spare parts to other engines.
- This diesel along with its classmate were given two nicknames, first being "Toffee Apples" because of the shape of their control lever and the second "Skinheads" because the first few engines didn't have the codebox on the front of the roof.
- Strangely, the British Railways logo is missing of this diesel.