Talks to avert train strikes before Christmas have broken down.
Operator ScotRail and the National Union of Rail, Maritime and Transport Workers (RMT) met but attempts to find a resolution failed.
RMT members at Scotrail are due to strike on December 22 and Christmas Eve.
The action is in support of former ticket inspector Scott Lewis who was dismissed after an incident over the type of ticket used by a member of the public.
Scotrail describes the industrial action as a "clear attack" on the travelling public at Christmas.
RMT members on the firm's sleeper services will also strike for 24 hours from the evening of December 21 and again from the evening of December 23.
A ScotRail spokesman said: "It is extremely disappointing that the talks failed to reach a solution. The RMT wanted the former ticket examiner to be reinstated."
Contingency plans aim to keep any impact on travellers to a minimum, the spokesman said.
"There is no doubt that the majority of our services will run," he continued.
"As always, we are available for further meaningful talks at any time."