47643 was purchased by the SRPS in 1995 after some of the members decided the previous year to preserve a Brush Type 4, and because a loco with ETH was required for testing of the societies mainline registered set of coaching stock. 47643 had been withdrawn back in 1991 with fire damage to the engine room wiring and had been dumped in Millburn Yard, Inverness. The SRPS bought the loco from a scrap merchant who had been unable to cut up the loco due to its remote location. It had also been based in Scotland most of its life. It moved by rail to Bo'ness in October 1995.

Over the previous 4 years, several parts had been removed, in particular the power unit which had been heavily robbed. The turbocharger, intercoolers, heat exchanger and several pistons, heads and liners had been removed. Replacements were obtained from a number of sources and within 12 months the power unit had been completely overhauled, the damaged wiring had been renewed, and all the other missing material had been fitted. Lack of time meant it was only possible to give it a quick coat of paint and it appeared in XP64 colours at the SRPS September 1996 diesel gala. Further work was done after this to complete all the mechanical and electrical tasks and the loco was fully repainted inside and out, being finished in Intercity ScotRail livery in time for the September 1997 diesel gala.

Since then, it has seen regular use at Bo'ness, including hauling the Railtour ECS trains to the junction with the main line at Manuel.It has made 2 trips to other railways since restoration. In July 2000, it took part in the East Lancashire Railway diesel week, then, in August 2001, it received a last minute invite to the Diesel weekend at the Keighley and Worth Valley Railway. During 2005 "643" traveled by rail together with 27 001 and 26 024 to the North Yorkshire moors Railway for their Diesel Gala.The locomotive is currently out of service pending repairs to a hole in the exhaust silencer and roof. It is hoped to carry out minor bodywork repairs and repaint the loco during 2008