A total of thirty Class 67 locomotives were built between 1999 and 2000 by Alstom, in Spain, for English, Welsh & Scottish Railway (EWS). These Bo-Bo configured diesel electric locomotives have a large fuel capacity, electro-pneumatic brakes and a top speed of 125mph (200km/h). The bodyshell is a monocoque load bearing Alstom design, whilst the bogies, also designed by Alstom, are of an "H" frame design.
The engine, traction motors and control electronics are the same as those used in the Class 66, but differ in that the traction motors are frame mounted, rather than axle hung, to reduce unsprung mass. The gear ratios have also been increased, allowing higher speeds and the cab is designed around a central driving position. The Class 67 locomotives are able to supply electric head-end power for passenger train heating and air-conditioning and are equipped for buffer and screw coupling, as well as also coupling via a buckeye coupler, attached on a swing arm mount.
The first locomotive to be delivered was 67003, arriving in October 1999, but plans for a rapid acceptance into service were delayed by loading gauge issues. The high axle load of the locomotive caused an initial speed restriction to 110 mph and modifications to the bogies were required, all thirty units being modified by June 2003.