It comes days before passenger numbers are expected to increase with a further lifting of Covid lockdown restrictions on Monday when hotels and other holiday accommodation across Scotland will be permitted to re-open.
Members of the Rail Maritime and Transport union (RMT) have voted by nine to two for a stoppage over an alleged breach of the train operator’s “dignity and respect” policy.
A total of 69 per cent of fleet maintenance staff voted in the ballot at ScotRail’s “outbase location” in Perth where trains are refuelled and stabled.
The result comes as ScotRail ticket examiners are due to join conductors in a series of Sunday strikes over holiday pay, which has closed down virtually the entire network outside the Glasgow area.
The stoppages are due to continue through May with the RMT threatening to extend them further if the dispute is not resolved.
It centres on other staff not being offered extra pay for working on days off, unlike drivers.
The firm’s four unions are also consulting members about a strike ballot over pay after being told any increase would have to be tied to efficiency gains.
RMT Scottish organiser Mick Hogg said the union’s national executive committee would consider what action to take in the Perth dispute.
He said it centred on the disciplining of a manager who was then moved to another site.
Mr Hogg said: "If this was one of our members, they would be dismissed.
"It is one rule for managers and one rule for employees.
"Dignity and respect within the workplace applies to everyone.”
ScotRail insisted any action would have no impact on services.
Engineering director Syeda Ghufran said: “I am disappointed with this outcome, despite an exhaustive investigation having taken place, in cooperation with the RMT.
“At a time when the railway faces the most serious financial crisis in its history, we need to work together to recover ScotRail, get passengers using the trains again, and build a more sustainable operation.
"Strike action is divisive and wrong.”