Rail passengers have been warned of severely reduced services on Northern trains on Saturday due to a third round of industrial action.
The operator said the limited services that will be running are expected to be “extremely busy” as people travel to major events in the north of England.
A reduced timetable will leave very few trains running before 9am and after 6pm, with only 30% of scheduled services expected to run.
Trains will not be running at all on some routes, while others will be limited and rail users were advised to check online before they travel.
“On those routes where we are able to operate trains, we expect all services to be extremely busy,” Northern said.
“We also have replacement bus services available on some routes where trains aren’t running.”
There will be further disruption to services between Manchester and Liverpool due to engineering work, the operator said.
The RMT is locked in a dispute with Northern over driver-only trains.
The union has accused Arriva Rail North of collapsing talks being held via the Acas arbitration service.
As well as running all day on Saturday, further strikes are planned on Saturday October 6, Saturday October 13 and Saturday October 20.
RMT general secretary Mick Cash said: “Arriva Rail North continue to refuse to match the best practice in the industry on the guard guarantee and seem hell-bent on continued conflict.
“In spite of the collapse of this week’s talks at Acas, RMT will not be deterred in its efforts and will continue to campaign both industrially and politically to ensure passengers using Arriva Rail North Train Services are afforded the respect they deserve and are provided with a continued and guaranteed safe, secure and accessible railway.
“The issue at the heart of the dispute remains the same – a safe, accessible and secure railway for all and we thank the travelling public for their continued support for RMT’s campaign.”