The Class 318 units were built in 1985-86 by BREL York and 21 three-car sets were constructed. The units were introduced in September 1986 as part of the electrification of the Ayrshire Coast Line. They were also deployed on the Inverclyde Line in small numbers.

The Ayrshire Coast Line were exclusively operated by Class 318s until 2001, when the new Class 334 Juniper units were delivered. By this time, some Class 318s began to work on the Argyle Line. Today the Class 318 units operate on the Argyle and North Clyde Line services.

Between 2005 and 2007, the Class 318s were refurbished. The refurbishment included the fitting of larger cabside windows, the removal of front end corridor connection, new vestibule draft screens and passenger interiors refreshed. The work was done by Hunslet Barclay at Kilmarnock.

Between 2014 and 2017, the Class 318 units were again refurbished. The work included the fitting of the universal toilet, interior refresh and a repaint to Scotrail saltire blue livery. The work was done by Wabtec at Doncaster.

This reskin requires the Southern Class 455/8 EMU Add-On from Steam, available from: http://store.steampowered.com/app/325963/