Drivers at Hull Trains are striking on Good Friday in a long-running dispute over the sacking of a colleague.
Members of Aslef will walk out for the day, warning that services will be disrupted.
The union says the driver was unfairly sacked after raising a safety issue at a meeting, which the company disputes.
Mick Whelan, general secretary of Aslef, said: “The company’s failure to act responsibly has enormous implications, not just for rail workers and passengers at Hull Trains, but for staff and passengers right across the wider rail network.
“This is a moral issue because we have a culture on the railway designed to keep everyone safe. Anyone who works on the railway should be able to report a safety concern without fearing they will be penalised, punished, or lose their livelihood. The company has behaved deplorably.”
A spokesperson for Hull Trains, said: “The safety of our customers and colleagues remains our number one priority.
“Aslef have declined two recent offers that we have made for constructive talks and Hull Trains remains open to dialogue.
“There are minor alterations to our timetable, with details published on our website. The majority of our services are still operating as planned.”
Hull Trains previously said it followed highly regulated industry standard agreements and procedures for safety.
The operator said most services ran during previous strikes over the dispute.
The company operates services between Hull and London King’s Cross, with stops at stations including Selby, Doncaster, Retford and Grantham.
