A smaller two track engine shed was provided south of the station and after closure in the 1990s it was used for the stabling of diesel and electrical multiple units.

It is currently known as Colchester Carriage Servicing Depot and units can be washed externally and cleaned internally on site.

However, the train was stopped at Brentwood as a timber viaduct at Mountnessing had subsided and it was unsafe to continue.

The Eastern Union Railway (EUR) arrived in 1846 and they also established an engine shed, this time to the east of the ECR station which they shared.

The early history of this structure was unhappy in that a fire on 25 January 1850 destroyed the engine house and three locomotives.

The contract was awarded in August 1890 and a new three road brick shed with a slated north light roof was built.

During World War I the turntable was replaced by a 65 foot model suitable for the longer more powerful locomotives operating in the area.

Towards the end of its life diesel locomotives were being fuelled from tank wagons on the depot site.

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.

With the introduction of the British Rail TOPS (Total Operations Planning System) in 1973, Colchester locomotives were allocated the code CR.

The two road shed was unused for a number of years although the lines through the depot were intact and used for stabling local DMUs or Thunderbird rescue locomotives.

This was to relieve the pressure on Norwich Crown Point depot which was working to accept new electric and bi-mode units into service.