Train passengers are being warned they could face major delays this bank holiday weekend.
People travelling on the East Coast Main Line between London and Peterborough are being urged to plan ahead because of key engineering works and industrial action.
The work is part of a billion-pound infrastructure upgrade.
Train operators on the affected routes say “journey times will be longer” between Saturday and Monday morning.
Engineering works will take place between Welwyn and Hitchin in Hertfordshire affecting services between London and Grantham in Lincolnshire as part of the multi-million pound East Coast Digital Programme (ECDP) work takes place
Services on the lines for Ely and Leicester will also be affected.
ECDP’s Ricky Barsby said: “The work we are delivering for the East Coast Digital Programme is imperative in allowing for improved, more reliable journeys for our passengers.
“We want to thank passengers for their patience and understanding in advance of the work and have carefully planned it so it causes the least amount of disruption as possible.”
Network Rail says delivering the upgrade will mean a more reliable railway with lower emissions with digital signalling being introduced.
The engineering works come at the same time as rail strikes across England on Saturday over pay and conditions.
The RMT union says about 20,000 members working for 14 train operating companies are expected to take part.
General secretary, Mick Lynch, said that its members would “continue fighting”.
The government called the move “disappointing” and said the RMT leadership was “cynically targeting” travellers.
The independent watchdog for transport users, Transport Focus, said passengers would be “frustrated”.
Director David Sidebottom said: “With many people set to visit family and friends as the summer winds down, the additional industrial action does not help the situation either.”