Train drivers are to stage two fresh strikes in a long-running row over pensions, threatening further disruption to services.
Members of the Aslef union at East Midlands Trains will walk out on June 23 and 25 in the latest phase of a campaign of industrial action.
The company attacked the action, saying that Aslef had accepted similar pension scheme changes at two other train companies without becoming involved in a dispute.
Managing director David Horne said: "We know that our passengers will be extremely angry to hear that Aslef is planning to cause further unnecessary disruption to their train services.
"Both the RMT and Unite unions have recommended acceptance of the same updated pensions proposals we offered to Aslef several weeks ago. Aslef also accepted the same pension contribution changes at two other rail companies. The action is indefensible and pure hypocrisy.
"Our drivers have already lost £1,200 through six days of pointless strike action and we are certain they don't want to lose any more money. We expect they will also be unhappy to hear that union leaders have called further strike action without reballoting their members.
"We have already demonstrated that we can successfully continue running services for passengers despite Aslef's action and we are committed to running as many services as possible on June 23 and 25."
Aslef's general secretary Mick Whelan said: "The company began to put out these smears only hours after agreeing a meeting for next Tuesday.
"On one hand they smile and promise open and honest talks, while on the other they sneak around calling the union names - and then they accuse us of hypocrisy.
"I have to say their ill-tempered outbursts do not bode well for an agreement to be made at next week's meeting. They are clearly more concerned with their egos than their passengers."