Originally fitted with a steam heat boiler, D120 was modified in 1973 by the addition of electric train heating equipment to operate the air conditioning fitted to carriages entering service in the 1970s. Two large lumps of concrete ballast reside in the rest of the former boiler room, to maintain the correct weight ratios.

The loco was withdrawn from service in 1987 and then purchased for preservation under the care of Waterman Railways and restored to run as D120 in BR Green. After a period out of use, 45108 passed into the ownership of the Peak Locomotive Company in 2008 and remains a member of their fleet.

Since 2008 the loco has been restored to operational condition with repairs carried to corroded air pipes and reinstatement of the ETH system amongst other works. 45108 is on loan to the ELR until 2022. Train heat capabilty makes 108 a versatile performer and especially useful for the Santa season. The loco is due a repaint soon when capacity is available at the ELR.