The British Rail Class 485 (or 4Vec, later 5Vec) electrical multiple units were originally built for the London Electric Railway from 1923-31 as its 'Standard' tube stock.

They were purchased by British Rail in 1967 and transported to the Isle of Wight to work 'mainline' services on the newly electrified Ryde to Shanklin line, where they worked for an additional quarter of a century. At the time of their purchase the units had already worked for over 40 years on the London Underground, but their introduction allowed the last steam locomotives on the line to be withdrawn.