The latest remarkable Colas Rail class 37 resurrection occurred in June 2018 with 37521 being restored to the active pool of locomotives rostered for Network Rail infrastructure monitoring trains. The locomotive, owned by HNRC and leased to Colas Rail enjoyed its final fling working for EWS back in 2004 during the autumn 'leaf busting' season working trains in and around Yorkshire. It was one of the few 'freight' 37's I was lucky enough to capture in my early days of the hobby with a camera who's results were varied at best! Having been off the mainline for over 13 years it's certainly great to see and hear the overhauled 37521 back on the national network!
Above 37521 'English China Clays' is seen bringing a RHTT set through Doncaster on 28th October 2004. 37516 in LoadHaul colours is on the rear of the train. Incidentally 37516 is another survivor and continues to see use on the mainline with West Coast Railways!
Below, 37521 13 1/2 years later approaching Basingstoke on 29th June 2018 working 3Z80 from Hither Green - Hither Green via Eastleigh.
