The RMT has announced that it will take nationwide strike action across the railways on March 16, March 17, March 18, March 30 and April 1 after what it describes as 'employers refusing to put any new offers on the table'.
The union represents 40,000 workers across Network Rail and 14 train operators, including Great Western Railway (GWR). RMT members working for GWR tend not to include drivers, who are mostly represented by the ASLEF union.
The strike on March 17 is set to affect Network Rail operations, meaning that while it may not directly affect the operation of trains, it is likely to have an impact on services due to the unavailability of RMT-affiliated Network Rail staff.
RMT members working for the railway operators will take strike action between 00:01 hours and 23:59 hours on March 16, March 18, March 30, and April 1, while Network Rail members will take action between 02:00 hours and 01:59 hours on March 17.
Confirming it has rejected the latest offer made by the employers as it did not 'meet the needs of members on pay, job security or working conditions.'
For this reason, it has announced a programme of strike action, which as well as the walkouts will include an overtime ban that will affect maintenance and operations work.
The RMT says that it is seeking an unconditional offer from rail operators and Network Rail - that is, a pay offer that does not alter working conditions such as the proposed closure of ticket offices or any potential redundancies.
RMT general secretary Mick Lynch said: "Rail employers are not being given a fresh mandate by the government to offer our members a new deal on pay, conditions, and job security.
"Therefore, our members will now take sustained and targeted industrial action over the next few months.
"The government can settle this dispute easily by unshackling the rail companies.
"However, its stubborn refusal to do so will now mean more strike action across the railway network and a very disruptive overtime ban.
"Ministers cannot continue to sit on their hands hoping this dispute will go away as our members are fully prepared to fight tooth and nail for a negotiated settlement in the months ahead."