Rail passengers are reminded to check before they travel this weekend, as some engineering work is planned for the network in East Anglia, mostly on Sunday and Monday.
Greater Anglia trains will be running direct to London on Saturday as normal on the Great Eastern Mainline from Norwich, Ipswich, Colchester and Chelmsford and on the Southend line.
However, on Sunday and Bank Holiday Monday, a rail replacement service will run from Ingatestone, on the mainline, and Billericay, on the Southend line, to Newbury Park. From there, Greater Anglia customers can use their tickets on the Central Line into London Liverpool Street.
Greater Anglia has booked nearly 140 buses so that customers planning to go to London on Sunday or Monday are still able to complete their journey.
Extra staff will be on hand at stations to help customers get onto the right bus.
Greater Anglia managing director Jamie Burles said: “We will make sure that customers are able to complete their journeys this weekend, even if part of the way is by bus.
“We apologise to customers for inconvenience engineering works may cause, but these engineering works are vital to improve the railway in East Anglia for everyone, making it more reliable for generations to come.”
Network Rail is due to install 1km of overhead wire at Brentwood, replacing wire from the 1950s which sags in hot weather leading to trains running at lower speeds in order to protect it.
Further works will also be carried out on the Crossrail project, to prepare for the connection of the Crossrail tunnel to the main line at Stratford.
On Sunday, Network Rail is carrying out engineering works from Stratford to Tottenham Hale. Services to and from Stratford will be diverted via Hackney Downs to Liverpool Street, and will not call at Lea Bridge or Stratford.
Throughout the whole bank holiday weekend, buses will replace trains between Peterborough and March, as Network Rail is building a new bridge at Whittlesey, which will allow trains to run at faster speeds.
Customers are advised to check before they travel, using the Greater Anglia website, Twitter or rail apps. They should also allow extra time to complete their journeys.
For more information visit www.greateranglia.co.uk/alterations.