The vehicle was built at Wolverton in 1962 as a Mark 1 BSK 35386 coach. In 1974 the last LNER designed Dynamometer Car DB999500 (previously DE320041) was damaged beyond economic repair during a slip brake test and BSK 35386 was modified as its replacement. It continued in departmental service until 2011 and was purchased by a GCR volunteer in 2016.