A fresh wave of rail strikes starts this morning amid bitter disputes over the role of guards and driver-only trains.
Members of the Rail, Maritime and Transport union (RMT) at Southern, Merseyrail and Arriva Rail North are due to walk out today and Monday, while Merseyrail workers will also go on strike on Sunday.
The Southern dispute started more than 16 months ago, with the RMT taking more than 30 days of strike action.
Merseyrail said a reduced train service will run across its network on strike days, with trains running from around 7am to 7pm on Friday and Monday and from around 8am to 7pm on Sunday, with no trains for a few hours in the middle of the day.
Arriva Rail North said it aims to run more than 900 services on Friday and Monday, mainly between 7am and 7pm, with services on some routes finishing earlier.
Regional director Sharon Keith said: "We have focused on ensuring our busier routes between major towns and cities maintain a good level of service throughout the day, while replacement bus services will be available on some routes where there are no trains. We are asking customers to plan ahead carefully and consider whether their journey needs to be made as all trains will be far busier than normal.
"It is disappointing that RMT has timed these two days of strike action to coincide with people returning to school, college and work after the summer holidays.
"During recent talks we underlined that we are prepared to guarantee jobs and current pay for all our conductors for the next eight years. Our offers to discuss every detail on the future responsibilities and training for on-board colleagues have been rejected by RMT.
"We urge them to get back round the table with us quickly and talk seriously about our modernisation, not take unnecessary strike action."