More than 40,000 RMT members from 14 train firms are set to strike in two days in September, sparking travel nightmares for rail users.
The walkout has been caused by disputes over pay, jobs and working conditions.
The 40,000 RMT members will stage a walk out on September 15 and 17.
It comes a day after it was announced members of the train drivers’ union Aslef will stage a separate walk out at 12 train companies on September 15.
The Transport Salaried Staffs’ Association (TSSA) earlier announced its members at nine train operating companies as well as Network Rail will walk out from midday on September 26, for 24 hours.
RMT general secretary Mick Lynch warned the industrial action will continue to happen for “as long as it takes”.
He added: "Our members have no choice but to continue this strike action.
"Network Rail and the train operating companies have shown little interest this past few weeks in offering our members anything new in order for us to be able to come to a negotiated settlement.
"Grant Shapps continues his dereliction of duty by staying in his bunker and shackling the rail industry from making a deal with us.
"We will continue to negotiate in good faith, but the employers and government need to understand our industrial campaign will continue for as long as it takes."
In separate disputes, Hull Trains and Arriva Rail London will also be taking one day of strike action on the 15th of September.
Negotiations between the union and rail industry have been ongoing but there has been no breakthrough or new offers from either Network Rail or the train operating companies in the national rail dispute.
In separate action, Aslef members at Avanti West Coast, Chiltern Railways, CrossCountry, Greater Anglia, Great Western Railway, Hull Trains, LNER, London Overground, Northern Trains, Southeastern, TransPennine Express and West Midlands Trains will strike on September 15.
Rail workers likely to be involved in the TSSA strike on September 26 include TransPennine Express, West Midlands Trains, Avanti West Coast, c2c, CrossCountry, East Midlands Railway, Great Western Railway, LNER and Southeastern.
TSSA union leader Manuel Cortes said yesterday: “The dead hand of Grant Shapps is sadly stopping train operating companies from making a revised, meaningful offer.
“Frankly, he either sits across the negotiating table with our union or gets out of the way to allow railway bosses to freely negotiate with us, as they have done in the past.
“The reason for the current impasse lies squarely at Shapps’ door and passengers are paying a high price for his incompetence and intransigence.
“I welcome the fact that negotiations are ongoing with Network Rail and the gap towards a resolution is narrowing. Time will tell whether a deal can be done to avert our next strike.
“I will be standing on our picket line in Liverpool and will be encouraging fellow delegates and Labour MPs to do likewise, so they can rightly show they stand shoulder to shoulder with those fighting the Tories’ cost-of-living crisis.”
