D6948

D6948 (37248) is a Class 37/0 owned by four members of The Growler Group. Like its stablemate 37215, it was built by English Electric at the Vulcan Foundry in Newton-le-Willows, and was delivered to British Railways' Cardiff Canton depot on 30th October 1964.

After three years working in South Wales, a transfer to Healey Mills (55C) near Wakefield followed on 1st August 1967. Five years of working around Yorkshire, Humberside and across the Pennines came to an end in January 1972 when D6948 returned to Cardiff Canton, where it would remain for the next twenty years, becoming part of the fabric of the South Wales railway scene. It was renumbered to 37248 in 1974.

A short move back to Tinsley followed in 1992 before another return to Cardiff in 1994. In 1995 the locomotive was transferred to Toton and allocated to the shadow pre-privatisation freight company Mainline, receiving that company's aircraft blue livery and the name "Midland Railway Centre." The purchase of Mainline by Wisconsin Central and the formation of EWS brought further moves — to Old Oak Common in 2000, Motherwell in 2001, and finally Crewe in 2003, where it was withdrawn and stored in December of that year.

After two years in store at Margam, the locomotive was purchased by three Growler Group members in conjunction with West Coast Railways Ltd, under an agreement for WCRC to restore it to working order and operate it on the main line. The locomotive entered WCRC service in 2006 and worked extensively across the national network, particularly in Scotland, including hauling the prestigious Royal Scotsman land cruise train. The loan agreement expired in 2009.

D6948 moved first to the GCR(N) at Ruddington before becoming a permanent resident at Toddington on the GWR in 2010, arriving in West Coast Railways livery and carrying its TOPS number 37248. Under preservation, the locomotive underwent an extensive multi-year refurbishment to 'as built' 1964 condition, including the reinstatement of steam heating and a return to BR green livery with small yellow warning panels.

After a period on the sidelines following its last diesel gala appearance in the summer of 2019, D6948 returned to active service in 2023.