Northern rail has rejected claims it deliberately posted notices claiming strike action planned by RMT union members had been cancelled.
The RMT announced the action last week in a dispute over plans to bring in more driver-only-operated (DOO) trains.
It said the rail company was "resorting to lies and dirty tricks to try and undermine our action", due to take place on 13 March.
Northern said the posters at Manchester Victoria station were put up in error.
The RMT announced the walkouts in a dispute with rail operators over plans to remove the responsibility of opening and closing train doors from guards.
'Pathetic and despicable'
General secretary Mick Cash said the measures will make trains potentially dangerous.
He described the posters as a "desperate move by a company that is prepared to resort to lies and dirty tricks to try and undermine our action in the guards safety dispute".
A spokesman for Northern said: "The poster is part of a customer communications pack sent to our stations. These always cover every eventuality, especially in the event of strike action, as this allows us to get information out as quickly as possible to customers.
"Unfortunately one of our stations displayed the wrong poster which was quickly removed."
A spokesman for the RMT union called the rail company's response "pathetic".
He said: "To try and lump the blame for this scandal onto the staff themselves is despicable."
"Instead of sinking to these kind of tactics they should be in a room with us negotiating a settlement."
Northern rail stressed it had received no communication from the RMT that planned strike action had been cancelled.
It said it remained committed to finding a resolution.
Staff at Southern rail and Merseyrail are also due to strike in a dispute over the role of guards on 13 March.