Rail companies are to stage two 24-hour strikes in worsening disputes over the role of guards and driver-only trains.
Members of Merseyrail and Arriva Rail North will walk out on October 3 and 5.
The strikes will coincide with the Conservative Party's annual conference in Manchester.
Mick Cash, RMT general secretary accused Arriva Rail North of "intransigence", adding: "
A petition in defence of guards on Merseyrail has attracted over 20,000 signatures.
Mr Cash said:
The Merseyrail strike will coincide with the first phase of work to transform Liverpool Lime Street mainline station by the end of 2018.
Between September 30 and October 22 Network Rail will embark on a major project to overhaul the station, helping cater for a predicted doubling of peak-time passengers by 2043.
No trains will enter or leave Lime Street mainline station for nine days, and many will be diverted.
Jan Chaudhry-van der Velde, Merseyrail's managing director, said:
Richard Allan, Arriva Rail North's deputy managing director, said:
Rail workers in the north are to launch a fresh wave of strikes in long-running disputes over staffing and driver-only trains.
Members of the Rail, Maritime and Transport (RMT) union at Arriva Rail North will walk out on Friday September 1 and Monday September 4.
Strikes will be held at Merseyrail on September 1, 3 and 4.
The union accused the companies and the Government of pressing ahead with controversial plans to extend driver-only operation.
RMT general secretary Mick Cash had a meeting with Arriva Rail North on Friday but accused the company of "intransigence", adding:
Alan Chaplin, Northern's managing director, said: