Railway workers have voted to indefinitely ban working overtime and rest days in a dispute over pay equality.

RMT members agreed "overwhelmingly" for the decision, which comes into force on ScotRail services from 12am on Wednesday.

The row centres around how drivers are being offered enhanced payments for working outside normal contracted hours, while other employees are not.

RMT general secretary Mick Cash said: "This dispute is about equality and justice across grades in the Scotrail workplace.

"It cannot be right that the company seem to value one group of workers over another."

He added: "Their approach to the rest day working payments, where they have only offered driver grades enhanced arrangements is nothing short of discriminatory.

"A driver working rest days is no different than any other member of front line staff working rest days.

"Each member is giving their rest time back to help the company to help run a service to passengers.

"All staff should be treated equally and fairly and that is all that the union is calling for. We remain available for further genuine and meaningful talks."

More than 2,000 RMT ScotRail members involved in the dispute are instructed not to volunteer to undertake any overtime and rest day working with effect from Wednesday, until further notice.

David Simpson, ScotRail operations director, added: "We remain in discussions with RMT to resolve this matter, and we plan to operate a normal service."