The second batch units were built to operate outer-suburban trains on the "Great Northern" route from London King's Cross to Stevenage, Cambridge and Peterborough. Like the first batch units, they were delivered in BR Blue/Grey livery. The units replaced the slam-door Class 312 units, dating from 1975, which subsequently transferred to the Great Eastern Main Line and London-Tilbury-Southend routes. Like the DC class 455 units, several aspects of the exterior were modified, with metal hopper ventilators replaced with larger panes of glass and the 'headcode indicator' flat front replaced with a rounded design.