Commuters to London have been urged not to travel after the London North Eastern Railway (LNER) service warned of major delays and cancellations.
LNER said a number of Hitachi trains from several train companies have been taken out of service today for checks as a "precautionary measure".
Due to this, LNER said services route-wide are subject to delays and cancellations and people were urged not to travel.
Those with ticket can defer their travel but they must ensure they make a new reservation on the LNER website.
A spokesperson for the service said: "Due to a problem under investigation, services route-wide are subject to delays and cancellations.
"Please DO NOT TRAVEL, tickets will be valid up to and including Sunday 16th May 2021 (a new reservation MUST be made)."
The issue is also affecting TransPennine Express trains between Newcastle and Liverpool.
A spokesperson for TransPennine Express said: "A number of Class 800 series trains from several train companies have been taken out of service today for checks as a precautionary measure, including our Nova 1 trains.
"This problem is being investigated by the train manufacturer and once trains have been checked, we hope to be able to release them back into service as soon as possible.
"This will affect a significant number of services on our Newcastle to Liverpool route and we are advising customers not to travel on this route today."