MPs are being urged to raise in Parliament how much money train companies have been given in compensation for the weather-related transport chaos.
The Rail, Maritime and Transport union (RMT) criticised the system under which Network Rail will have to pay out to private rail companies.
General secretary Mick Cash said: "RMT is demanding to know how much the taxpayer has shovelled in to? the pockets of the private train companies during the adverse weather over the past week under our rotten rail franchising system.
"The whole racket on our railways was rigged from the off by the Tories so that the profits are privatised and the risks are carried by the public.
"It's a scandal that has led to a bail-out culture on our railways which is being exploited by the train operators while passengers are freezing in luggage racks on broken-down trains.
"RMT will be raising this issue with the unions' parliamentary group and we are demanding answers and not the usual hot air we have come to expect from Transport Secretary Chris Grayling and this Government."
A spokesman for the Rail Delivery Group said: "These payments are overseen by the rail regulator which says that they keep costs down for taxpayers and farepayers, and they are completely separate from the money customers rightly receive for delays.
"The payments compensate train operators for lost revenue when fewer people travel due to disruption and they encourage rail companies to work together to improve punctuality."