Workers at two rail companies will launch a fresh strike today in the long-running dispute over the role of guards on trains.
Members of the Rail, Maritime and Transport union on Greater Anglia and Arriva Rail North (Northern) will walk out for 24 hours, mounting picket lines outside stations.
Arriva Rail North said it will run more than 1,300 services, mainly between 7am and 7pm, accounting for around two thirds of the normal weekday timetable.
A message to passengers said: "As the overall number of trains running will be reduced, we 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.
"During the RMT strike action we expect all services to be busy, especially in the morning and evening peak periods, and advise you to allow extra time to travel."
Jamie Burles, Greater Anglia managing director, said: "We'd like to reassure customers that we will be running a full service using our contingency conductors.
"In recent weeks, we have had some constructive talks with RMT union officials and offered a proposal which we hoped would resolve this issue. Unfortunately, the RMT has rejected it.
"Our position remains the same: We highly value our conductors, we're keeping them on our trains, but we want them to concentrate on customer service rather than opening and closing doors. We will continue to talk to the RMT to try to find an acceptable solution."
Conductors are on 40% of Greater Anglia services. The remaining services, mainly commuter trains to London Liverpool Street from Essex, Cambridge, Hertfordshire and Suffolk, do not have conductors.
RMT general secretary Mick Cash said: "Yet again the intransigence of private rail companies operating in England over the key issue of the guard guarantee means that we have no option but to announce further strike action in the separate disputes on Arriva Rail North and Greater Anglia.
"We are drawing attention to the ludicrous situation that means we are able to reach agreements in Wales and Scotland on the guard guarantee but not on a raft of key franchises in England. If it's good enough for Wales and Scotland to put rail safety first then it should be good enough for the rest of Britain.
"We have long detected the dead hand of the Government interfering to stop us reaching negotiated settlements in the current disputes and it's about time Chris Grayling (Transport Secretary) stopped playing politics with passenger safety and started taking the issue seriously."
Planned strikes on South Western Railway have been called off to allow talks, while the union is also discussing the same dispute with officials from Merseyrail.