the british rail class 508 electric multiple units ("emus") were built by brel at york works in 1979-80. they were the fourth variety of br's then-standard 1972 design for suburban emus, eventually encompassing 755 vehicles and five classes (313/314/315/507/508). they have mostly worked on the merseyrail network since 1983, and continue to do so, now refurbished by alstom's eastleigh works.