The units were introduced fully on 29 September 1986 as part of the electrification of the Ayrshire Coast Line between Glasgow Central and Ayr\/Ardrossan with alternating current ( AC ) overhead lines .
The units were introduced fully on 29 September 1986 as part of the electrification of the Ayrshire Coast Line between and \/ Ardrossan with alternating current ( AC ) overhead lines .