Rail passengers are facing “major disruption” on the East Coast Main Line due to damage to overhead power lines.
National Rail says the cables are damaged between Retford and Newark North Gate.
It said trains between Doncaster and Grantham were delayed by up to two hours or cancelled.
Shadow chancellor John McDonnell has tweeted that the disruption means he will not be able to appear on Thursday night’s Question Time.
The BBC political discussion programme is being filmed in Sunderland.
Gavin Powers, a commuter from Doncaster, described the scene at stations as “packed and chaotic” on his Twitter feed.
Virgin Trains has advised people not to travel.
Three rail replacement coaches are running between Grantham and Doncaster, a National Rail spokesman said.
A further three coaches are running from Newark but there is no estimate as to when they will arrive as a result of a crash on the A1 near the town, he added.
The following routes have been affected by the problem:
- Grand Central between Sunderland / Bradford Interchange and London Kings Cross
- Hull Trains between Hull and London Kings Cross
- Virgin Trains East Coast between Edinburgh / Newcastle / York / Leeds and London Kings Cross
Network Rail said its engineers were working to resolve the problem and apologised for the disruption.
A spokesperson for Virgin Trains said: “We’re doing our best to keep customers moving during this disruption.
“Customers who do not wish to travel today can postpone their journey until tomorrow.”