These units were used by British Rail from the start of electrification in Glasgow in 1960. Initially the units worked between Helensburgh Central and Airdrie and various branch lines on the North Clyde area. They were later introduced to the South Clyde area in 1962, working from Glasgow Central to various destinations. This book covers both classes from the BR era through to privatisation and beyond. With the advent of more modern multiple units such as the Class 314 from 1979, a reduction in the use of the Class 303 and Class 311 took place. One Class 303 has survived into preservation at Bo'ness, and part of a Class 311 unit is based at the Summerlee Heritage Centre at Coatbridge near Glasgow.