Network Rail has been criticised after it emerged that two de-icing trains were out of action during last week's snow because they were being serviced.
Kent MP Greg Clark said he was "flabbergasted" to hear Network Rail's de-icing trains were undergoing maintenance during the winter.
Network Rail said other trains were being used in place of the de-icers.
The firm said that to suggest the de-icers would have kept the railway open was just wrong.
Mr Clark found out about the maintenance of the de-icing trains from Charles Horton, managing director of Southeastern, during a meeting at the House of Commons between the rail firm boss and MPs.
The Conservative MP for Tunbridge Wells said: "Although the amount of snow was exceptional, I was flabbergasted to be told by Charles Horton that two of Network Rail's crucial de-icing trains had been sent away for their annual service at the end of November so were out of action last week.
"It is farcical that de-icing trains should go in for maintenance in the winter, when they are needed, rather than during the summer, when they are not."
Mr Clark also criticised Southeastern for "failing to run trains and failing to communicate with the public".
A Network Rail spokesman apologised to passengers and said: "During last week's winter weather in Kent, we brought in extra resources from other parts of the network which were not affected.
"These more modern locomotives were able to do much more than the piece of kit that was being upgraded."
Mr Horton also apologised to customers for the disruption and said Southeastern had already made changes to improve the service and information provided to passengers.
He said: "We are sorry that many of our passengers had severely disrupted services last week due to the snow and icy conditions on the track.
"Ice on the conductor rail makes it impossible for trains to draw electricity, causing major disruption.
"Network Rail worked hard to clear the snow and keep the rails free of ice, but despite their efforts large parts of the network were closed due to the very heavy snowfall."
The RMT union has called for all private companies involved in the disruption last week to be stripped of their contracts to de-ice tracks.
RMT general secretary Bob Crow said: "The scandal of the total failure of the private companies to deal with the cold snap in the South East goes from bad to worse.
"There is now an overwhelming case for Southeastern and the private companies responsible for de-icing works to be stripped of their contracts and the work returned to direct public ownership and public control."