The British Rail Class 57 is a family of diesel locomotives produced by reconditioning and re‑engining older Type 4 locomotives. Built between 1997 and 2004 by Brush Traction, the Class 57 machines took the bodies and running gear of earlier locomotives and fitted them with modern power units, controls and auxiliary systems. The programme turned surplus and aging locomotives into useful, cost‑effective traction for freight and passenger use.
Origins and conversion
The Class 57 conversions started from the original Class 47 fleet introduced in the mid‑1960s. Rather than constructing entirely new locomotives, the rebuilds retained the basic bodyshell and bogies while replacing prime movers, electrical equipment and cab systems. The work was carried out by Brush Traction and paid off in a comparatively fast, economical programme that extended the service life of a proven design.
Design features and variants
Key features of the Class 57 include replacement of the original engines with American‑built EMD two‑stroke diesel units, refurbished traction alternators and updated control electronics. Some members of the class were fitted with train supply or heating equipment to allow use on passenger services, while others were prepared primarily for heavy freight. The conversions produced locomotives with improved reliability, distinct engine acoustics and better tractive performance than many of the unrebuilt predecessors.
Service roles and operators
Class 57s have been employed in a variety of roles: hauling freight trains, rescuing failed trains, working charter and excursion services, and providing ad hoc passenger traction where needed. They proved especially useful to operators seeking a flexible locomotive without the cost of new build units. The first named example entered traffic with Freightliner and was informally celebrated by crews; names and liveries have varied between operators over the years.
Nicknames, reception and legacy
Enthusiasts and railway staff often called the Class 57s "bodysnatchers" or "zombies" because the original Class 47 bodywork was reused while the heart—the engine—was swapped. The conversions are seen as a pragmatic example of reuse in British railroading: by modernising core systems on an existing platform, operators gained useful locomotives at lower cost and with shorter lead times than new construction. Documentation and further technical detail can be found in fleet summaries and preservation records maintained by rail groups and manufacturers; see general references from British Rail era histories and later works by manufacturers such as Brush Traction for background.
Over time some Class 57s have been withdrawn, preserved or converted again to other duties, while others remain in active service with a mix of freight and passenger operators. The class illustrates how rebuilding can extend useful life and adapt older designs to changing operational needs. For more technical specifics and a list of individual locomotives, consult specialist locomotive registers and operator fleet lists available from industry sources and enthusiast publications; see also manufacturer and fleet pages linked above and dedicated resources at Class 57 information.