Specification is as follows:
Fully detailed and painted cab
5 pole skew wound motor with scale speed gearbox
In tender TTS sound system and speaker
Loco and tender wheel electrical pickup
Separate hand rails
Additional parts allowing for late and early variations
Various internal cylinder covers
Sprung Buffers
Brass Axle Bearings
6021 was completed in June 1930 and allocated to the GWRs primary London locomotive shed at Old Oak Common. Allocated to Plymouth Laira in the spring of 1959 6021 had returned to Old Oak Common before being withdrawn from service there in September 1962.