The Rail, Maritime and Transport union (RMT) said the Dutch firm was “declaring all-out war on their workforce”. Hundreds of conductors are being balloted for action after ScotRail sent staff proposals for them to be given a reduced role on a new fleet of electric trains from next year.
Drivers would take over the operation of carriage doors, while lower-paid ticket examiners would take over fare checks on some services.
The Scotsman revealed plans for the vote last month.
The RMT said Abellio was seeking to coerce staff at the company’s other train firms, Great Anglia and Merseyrail, to take part in training courses to become stand-in conductors.
General secretary Mick Cash said: “The attempt to coerce staff from elsewhere in Abellio’s UK operations into joining this scab-army is nothing less than a declaration of war by ScotRail on its workforce as the RMT ballot continues.
ScotRail confirmed it was preparing for possible industrial action. A spokeswoman said: “It will come as no surprise to anyone that we are making contingency plans as to how we run a service for our customers in the event this needless strike takes place.”