Northern Rail users across the region will be hit by severe travel disruption today as members of the RMT stage a walk-out in the bitter dispute over the role of guards.
The train company is expected to operate a reduced service of around 65% of the normal weekday timetable between 7am and 7pm.
Rail replacement buses will also be running, although Northern has said it expects these to be "extremely busy".
A spokesman for Northern said: "To help keep you on the move during RMT strike action on Wednesday, we will run more than 1,300 services.
"The majority of available trains will operate between 7am and 7pm as we focus on running as many trains as we can to get you into work and home again.
"As the overall number of trains running will be reduced, we do expect trains and any replacement buses we operate to be extremely busy. Please allow extra time for journeys, plan carefully and consider whether travel is necessary."
RMT general secretary Mick Cash said: "This dispute is about public safety and the fact that Northern can't or won't grasp that basic fact leaves us with no option but to strike.
"Passengers will understand that the key issue is about putting public safety before private profit and we thank them for their continuing support."
A Transport Department spokesman said: "The RMT is attempting to disrupt passengers as part of its political game. However, rail companies are keeping passengers moving with the large majority of services running as planned.
"This dispute is not about jobs or safety - employees have been guaranteed jobs and salaries. In fact at Southern Rail, where these changes have already been introduced, there are now more staff on trains.
"The independent rail regulator has said driver-controlled trains, which have been used in this country for more than 30 years, are safe."
Southern, South Western Railway and Greater Anglia are also striking on Wednesday and Thursday and a 24-hour walkout is also being held by union members at Merseyrail today.
For more information about travel on Northern Rail today see here