Following nationalisation the shed became part of the
Eastern Region of British Railways, and under the British Railways shed numbering scheme, Colchester was allocated the code 30E. By this time it was no longer part of the Ipswich district but part of the
Stratford district. The modernisation of the Great Eastern Main Line saw Colchester lose its main line allocation and
Ipswich and
Stratford engine sheds were then the nearest sheds with a main line allocation. Towards the end of its life diesel locomotives were being fuelled from tank wagons on the depot site. The old depot closed on 2 November 1959. The new electric multiple units were maintained at Clacton and Ilford and sidings south of the rebuilt station electrified sidings were provided for overnight stabling of commuter stock. A new two track modern depot was built and retained an allocation of shunting locomotives and following the closure of Ipswich and Parkeston engine sheds the shunting locomotives from these depots were allocated to Colchester for maintenance purposes although spending most time out based at those locations. During the 1970s and 1980s the allocation consisted of
Class 03,
Class 04 and
Class 08 locomotives. The class 04s disappeared in the early 1970s but Class 03s which worked the Ipswich Dock lines were retained until the 1980s before the depot became all Class 08. With the introduction of the British Rail
TOPS (Total Operations Planning System) in 1973, Colchester locomotives were allocated the code CR. Gradually as traffic declined and trains were operated in block loads and shunted by their own locomotives the allocation reduced and eventually the depot closed to traffic in the 1990s although visiting locomotives continued to stable in the depot area. ==The privatisation era (1996-present)==