Anticipating many years of further service BR designed a refurbishment programme for class 37 locomotives in the 1980s, and a ;group of locomotives were equiped with Electric Train Supply (train heating) to work with Mk.2 and air-conditioned coaches as these were being cascaded to secondary routes. This group was allocated sub-class 37/4 and allocated to the Regional Railways locomotive pool, employed on services in, to and from Wales, the Welsh borders and in the Scotish highlands. As passenger locomoitves many of the class received regional names. 37422, one of the wales allocated locomotives, was named Robert F Fairlie after the steam locomotive engineer whose design for a flexible bogie-mounted steam locomotive can be seen working today on the Festiniog Railway. This locomotive was one of the class which also received the Regional Railways blue and white stripe livery, similar to the livery designed for the new Sprinter multiple unit trains.