and modified brake blocks for working the heavy trains to Ravenscraig. These were all renumbered back to their original numbers by the end of 1988. The second set of locos were rebogied at various depots with the regeared cast frame type 'CP7 Bogie'. Bogies from the English Electric Deltics, Class 50 and Class 37s are largely interchangeable with only modification to traction motor gearing, to in the case of the 37s, and access step positions needing alteration between the classes. The fuel capacity was doubled by using the redundant train heating boiler water tanks but no other changes were made. Class 37/4 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. After the extensive refurbishment, the locomotives were allocated the 37/4 sub-class, following the trend of renumbering 'ETH' fitted locomotives xx/4s, (e.g. 474xx and 314xx). The next chapter saw the entire sub-class pass to Transrail Freight, which was one of the three regional freight operating companies prior to the privatisation of the entire British Rail network. Over the years, the locomotives have received a large number of liveries: BR Green, Regional Railways, Trainload Grey, EWS maroon, Transrail Freight, BR Large Logo and Mainline, to name a few. The Cambrian, North Wales Coast, Rhymney, West Highland, South Wales and West Country all benefited from the use of 37/4s. Locomotive hauled operations had virtually ceased by the early 2000s, thanks to the widespread introduction of second-generation diesel multiple units and the replacement of loco hauled trains by multiple units, although the sub-class did hold out on the Cardiff–Rhymney trains for Arriva Trains Wales for some years. 37411 and 37425 were specially painted to mark the end of loco-hauled services on the line, in April 2005, these repaints being funded by Arriva. In late 2010 DB Schenker put all of its remaining 37/4s up for sale, with many examples expected to be sold for scrap. Direct Rail