Class 37 - Colas - 37421 - DCC Sound Fitted37421 Colas Rail Stored by EWS at Motherwell in March 2005 and sold for preservation at the Pontypool & Blaenavon Railway in 2009, No. 37421 was one of four Class 37s that was purchased by Colas Rail in 2013 for a return to the main line, along with Nos. 37116, 37175 and 37219. While the latter pair debuted for their new owner in the middle of 2014, it would be another year before No. 37421 would re enter traffic along with BR green liveried former