FirstGroup PLC's (LSE:FGP) Avanti West Coast conductors have voted to go on strike for three days either side of Christmas after being asked to work on their days off.
The train company, 70% owned by FirstGroup and 30% by Italy's Trenitalia since October, had proposed new working arrangements for conductors, also known as train managers, to work on their days off when there are staff shortages.
Members of the RMT trade union voted to reject the proposal and go on strike.
This vote sends "a clear message to management that the current arrangements are unacceptable", said Mick Lynch, general secretary of the RMT trade union.
"Train Managers are being treated unfairly compared to senior managers, who receive significant payments for covering these roles.
“Our members have had enough, and this strike action demonstrates their determination to win a fair deal."
He said the union remains ready to reach a negotiated settlement.
Rail services on all three days are expected to be limited, the BBC reported, with a revised timetable for 22 and 23 December to be made available on Saturday December 14.