12134 was part of the first batch of production Mark 3A coaches ordered by BR to lot number 30877 in November 1973 and constructed at Derby Litchurch Lane works during 1975/6, coming off the production line at the same time as the first production HST trailers. Built for West Coast main line services, 12134 spent nearly thirty years operating on the route for British Rail and Virgin Trains until being displaced by new Pendolinos in August 2003.
After West Coast service 12134 moved to ScotRail for 16 months from May 2004 until September 2005 to operate on the Edinburgh to North Berwick services. Displaced from Scotland by EMUs, it was then placed into store. Following the award of a new East Coast franchise, in December 2007 12065 was selected to be part of a fleet leased to National Express to provide extra stock for the route.
Following the abandonment of that plan 12134 was moved back into storage, initially at the former ICI site at Wilton on Teesside, until purchased by Direct Rail Services in March 2013. Once again, no return to traffic was forthcoming and it was stored at Barrow Hill.
Purchased from Direct Rail Services on 16th August 2017, 12134 was moved from Barrow Hill to Ruddington on the Great Central Railway (Nottingham) on 30th August 2017, where it is currently undergoing overhaul before returning to traffic.