use of Class 317 units out of Euston again proved to be short-lived. In 1989, the second batch of new Class 321 were introduced onto WCML services. The Class 317 units were again displaced, this time to the Great Northern and West Anglia routes out of London King's Cross and London Liverpool Street, where they joined the second batch units. Therefore, for the first time, the entire Class 317 fleet was operating in the same place. Class 317/2 The second batch of 20 units was built in 1985–1986 and were classified as Class 317/2. Units were numbered in the range 317349–317368. A further four units were built in 1987 and numbered 317369–317372. These units have same DTSO(A)-MSO-TCO-DTSO(B) composition as Class 317/1 units, and have vehicles numbered in the following ranges: DTSO(A): 77200–77219 and 77280–77283 MSO: 62846–62865 and 62886–62889 TCO: 71734–71753 and 71762–71765 DTSO(B): 77220–77239 and 77284–77287 All vehicles in this batch were constructed at Holgate Road Carriage Works. 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. In 1986, the route came under the control of the newly created Network SouthEast, which introduced a bold new blue, red and white livery. The extension of the overhead line equipment soon allowed the units to work services on the West Anglia route from London Liverpool Street to Cambridge. In 1992, electrification spread north from Cambridge to Ely and King's Lynn, allowing the replacement of locomotive-hauled trains. The closely related Class 318 units, which were built for the Ayrshire Coast electrification in Scotland, are effectively a three-car version of the same design, but with a lower speed capability of 90 mph, and with traction motors provided by Brush instead of GEC. Operations With the privatisation of Britain's railways, the Class 317 fleet was incorporated into the West Anglia Great Northern (WAGN) franchise. Since then, various changes occurred to the fleet, as units were swapped and franchises changed. The following