the british rail class 57 diesel locomotives is a diesel locomotive that was built by brush traction between 1997 and 2004. they are rebuilds, with new engines, of older class 47 locomotives, originally introduced in 1964–1965. they are known as "bodysnatchers", or "zombies" to enthusiasts, because the shell (body) of the class 47 has been stripped, rewired and re-engined. the first ever class 57 named was “freightliner envy” after the first one entering freightliner.