These will take place at Romford and Ilford as well as improvements at stations including Forest Gate, Goodmayes, Harold Wood, Gidea Park, Chadwell Heath and Brentwood.
Platform extensions will allow longer, higher capacity trains to run, and new lifts to enable step-free access will be installed at many stations along the route.
The detailed design phase will commence in early 2014 and main works will take place between late 2014 and 2017.
Other works will include various infrastructure improvements, such as extra train stabling capacity and turnback facilities that will improve the reliability of passenger services.
Peter Mason, Network Rail’s Crossrail Senior Programme Manager, said: “Network Rail is undertaking a major upgrade of the existing rail network that will benefit passengers and freight customers, including a significant programme of track renewals as well as station improvements under the Crossrail programme.”
Under the Crossrail programme, Network Rail is responsible for the upgrade of 43 miles of track in total, as well as improving 27 stations from Maidenhead in the west to Abbey Wood and Shenfield in the east.