Despite claims by EWS these locos were the forerunner of the Class 66's, designed and developed by Foster Yeoman and General Motors , La Grange, Illinois and fitted with a GM 645E3C Diesel Engine producing 3300HP and GM Alternator and Traction Motors. Built for 3 private UK buyers this being reflected in the numbering 59/0 (Foster Yeoman), 59/1 (ARC) and 59/2 (National Power - now owned by DBS.