Network's Rail's 24-hour strike over the Spring bank holiday is the first test of industrial relations for the new Conservative government.
The Tories are planning tough new laws to stymie the power of the unions in calling strikes but with an 80% ballot turnout, the RMT was well above the government's proposed threshold.
RMT leader Mick Cash said: " We have a massive mandate for action which shows the anger of safety-critical staff across the rail network at attacks on their standards of living and their job security.
"It is appalling that NR are refusing point blank to take this dispute seriously, to understand the deep-seated grievance felt by their staff and to come forward with a renewed offer which protects pay, jobs and safety."
Network Rail has tabled a new pay offer to the RMT, Unite and TSSA unions and with talks continuing, could a deal be close?
A national rail strike is planned to take place on Monday and Tuesday - so what are your rights if your travel is disrupted?
Tube bosses have revealed the full extent of disruption to London Underground services if next week's national rail strike goes ahead.