Network Rail confirmed a “severely limited service” will be available for passengers during next week’s strike action as back-up staff will step in to keep vital services running.

However, as they’re a fraction of the usual workforce, Network Rail said only around half of Britain’s rail network will be open on strike days with a very limited service running on lines that will only be open from around 7:30am until 6:30pm.

Last week RMT announced three days of strike action to take place on Tuesday 21, Thursday 23, and Saturday 25 June, impacting 13 train operating companies. It comes amid the biggest dispute on the network since 1989 over pay freezes and planned job cuts.

And on 21 June, the rail strike action will coincide with a separate, second walk out by London Underground RMT members.

Network Rail said a special railway timetable operating across England, Scotland and Wales from Monday 20 to Sunday 26 June will be published this Friday “to offer the best service possible for passengers despite the unwarranted industrial action planned by the RMT union”.

However, it urged passengers who must travel to plan ahead, (see the National Rail website) especially as some last services from London to Scotland, for example, will leave in the early afternoon.

Andrew Haines, Network Rail chief executive, said: “Talks have not progressed as far as I had hoped and so we must prepare for a needless national rail strike and the damaging impact it will have. We, and our train operating colleagues, are gearing up to run the best service we can for passengers and freight users next week despite the actions of the RMT.”

Steve Montgomery, chair of the Rail Delivery Group, said: “These strikes will affect the millions of people who use the train each day, including key workers, students with exams, those who cannot work from home, holidaymakers and those attending important business and leisure events.

“Working with Network Rail, our plan is to keep as many services running as possible, but significant disruption will be inevitable and some parts of the network will not have a service, so passengers should plan their journeys carefully and check their train times.”

On the days that follow the strikes (22, 24 and 26 June) the whole network will reopen but Network Rail said passengers should also expect disruption on these days “as the strike days chosen have been designed to inflict as much disruption as possible, with not enough time between the strike days to fully recover to a normal service”.

Meanwhile the Transport Salaried Staffs’ Association (TSSA) said over 700 members at train operators C2C, LNER and Northern will be balloted for industrial action in a dispute over pay, conditions and job security. The earliest that industrial action could be taken is 20 July.