Workers on Virgin Trains West Coast are to stage six 24-hour strikes in December and January in a dispute over pay.
Members of the Rail, Maritime and Transport union will walk out on December 15 and 22 and on January 5, 8, 26 and 29.
The union said around 1,800 train managers, on-board catering staff, station and clerical workers will be involved in the action.
Virgin said it will run the majority of its services during the strikes.
RMT general secretary Mick Cash said: "Our members on Virgin West Coast are striking for workplace equality and workplace justice.
"All our members are demanding is a suitable and equal offer to that given to drivers to buy out their claim for a reduction in the base working week.
"We have made it clear to the company that the inequality and underhanded approach of Virgin will be fought tooth and nail. We will not accept our members being dealt with less favourably than others.
"The message needs to get through to Sir Richard Branson on his luxury island retreat in the sunshine that those who are financing his lifestyle through their hard graft have had enough and are prepared to fight for justice in their workplaces."
Phil Whittingham, managing director for Virgin Trains on the west coast, said: "The RMT leadership is attempting to cause disruption when many will want to travel by train to spend time with loved ones. We have explored a generous 3.6% pay increase, however the trade union's leadership is insisting on 4%, double the 2% average increase seen across the UK this year.
"We know how important it is for friends and families to get together over the festive season, so we will keep the majority of our trains running with fully-trained staff on board and at stations. We remain open to continuing talks with the RMT."
Virgin said it had informally offered a 3.6% pay increase for 2017/18 backdated to April 2017, and a deal for the following year of next January's RPI inflation plus 0.2%.
"The offer has been rejected by the RMT leadership which is insisting on a 4% increase for this year, followed by an increase the following year of RPI plus 0.25%. Any informal offer needs approval by the Department for Transport before being agreed," said Virgin.
Passengers take over 37 million journeys every year on the Virgin Trains west coast route, which serves 49 stations between London and Glasgow, including Birmingham, Liverpool and Manchester.