The British Rail 4-REP electric multiple units were built by BR at York Works from 1966-1967 and 1974. The units were built to power the 4-TC trailer units on services on the South Western Main Line. Fifteen four-car units were built. The motor coaches were new build, but the trailers were converted from Mk1 hauled stock. They were initially classified as Class 441 and numbered 3001-3015. This was later changed to Class 430, under which they spent the majority of their working lives. Shortly before withdrawal they were reclassified Class 432 and the units were renumbered to 2001-2015.