Union leaders will this week consider their next move in three bitter disputes over staffing on the railways and driver-only trains.
The Rail, Maritime and Transport union is embroiled in long-running rows with Southern, Northern and Merseyrail, which have sparked a series of strikes.
The union has called on the train companies to drop their plans in light of the election result.
Mick Cash, RMT general secretary, said: “RMT's disputes on Southern, Northern and Merseyrail not only remain on but are now right at the top of the national transport agenda as the chaotic, minority Tory Government lurches from chaos to crisis."
The train companies pursuing the politically-motivated drive to rip apart the safety culture on our railways should wake up to the new reality and pull their plans with immediate effect.
“RMT is demanding that the axing of the guards is reversed and the union will challenge Theresa May and the transport ministers in her minority government - whoever they may be - every step of the way as we step up the fight to put safety and access to services before private profit and greed.
"RMT will also ramp up the campaign for public ownership of the railways as the minority Tory Government collapses into chaos and recrimination."