With ETH (Electric Train Heating) replacing 'steam heated' coaches, some of this class received ETH Supply when refurbished at Crewe Works during 1985 and 1986. During this refurbishment, the locomotives also received regeared CP7 bogies and the English electric generator was replaced with a Brush BA1005A alternator. Extensive re-wiring, as well as a full repaint into BR Large Logo was undertaken. The modifications allowed the rebuilt locomotives to work passenger trains all year round, with the 31 strong fleet being split between Wales and Scotland, Scotland receiving the first 25 and Wales the other six.