[1] During a press run on 29 June 1937, 6220 set a new speed record on the West Coast Main Line.
Clark and fireman C. Lewis (with Robert Riddles (engineer) and inspector S. Miller on the footplate), pushed the Stanier pioneer to a claimed speed of 114 miles per hour on Madeley Bank south of Crewe, which broke the previous record of 113 mph set by the rival LNER.
[2] However, the celebration was premature, as the footplate team realised the train was still making 110 mph only a mile and a half from Crewe station.
This was only broken the following year by the LNER with A4 Class 4468 Mallard, which reached 126 mph whilst trialling a new quick action braking system.
[6] It was painted LMS 1946 black livery in September 1947, followed by BR standard express blue from January 1950 to April 1952.