Witham MP Priti Patel has expressed her concern over the delays in installing new points at Chelmsford, which has led to service restrictions and over-crowding on trains into London during the morning.
New points are being specially manufactured and due to be installed on the night of Thursday 11 June 2015.
However, until this work is complete, commuters will see be affected by the cancellation of the 06.25 train service from Kelvedon and overcrowding on later services.
Witham's MP Priti Patel, who has written to Network Rail and Abellio Greater Anglia about the problems and impact on services, said: "With the replacement works now pushed back further into June, commuters will have been affected by service restrictions for over a month.
"This situation is very concerning and I expect Abellio and Network Rail to mitigate the impact as much as possible, look to put in extra carriages on services, and ensure that the new points are installed as now planned."