SCOTRAIL bosses have been accused of an "underhand and provocative" attempt to foil a possible conductors' strike by training up other staff to fill their posts.

A leaked letter from the Transport and Salaried Staffs' Association (TSSA) warns that their members could face "undue pressure" from ScotRail management to attend conductor training sessions amid a looming threat of industrial action by colleagues in the RMT union.

RMT announced earlier this week that it will begin balloting its members for strike action after failure to secure guarantees from management that driver-only and driver-controlled operations - where trains run without a conductor, or guard - would not be extended during the lifetime of the franchise.

The ballot will open on May 24.

In the letter to Scotland's new Transport Minister Humza Yousaf, TSSA General secretary Manuel Cortes expresses concern that ScotRail has written to staff, including TSSA members, "asking them for their availability to attend [conductor] training".

He continues: "It is not clear whether our members can opt out or refuse without recourse.

"This leaves them vulnerable to undue pressure by senior management to attend training and conflict with their RMT union colleagues who exercise their lawful right to take industrial action.

"TSSA deplores the use of our union members and other staff to help weaken any legitimate industrial action by another union and we see this action by Abellio ScotRail as underhand and provocative."

Mr Cortes added that ScotRail were "happy to gamble with the safe operation of the railway" by using "unqualified and unlicensed staff, who have no experience".

He urged Mr Yousaf to instruct ScotRail to stop training other grades for conductor posts.

Mick Hogg, Scottish regional organiser for RMT, said ScotRail's intervention "makes a mockery" of claims that managers are open to negotiations.

He said: "ScotRail have exposed themselves for what they are, liars who will use every dirty trick in the book to compromise passenger safety and bulldoze through driver-only operations in the name of profit."

ScotRail insist that no employee will be forced to attend conductor training.

A spokeswoman for ScotRail said: “We are preparing in case of industrial action. Our priority will be to run as many rail services as possible during the period of industrial action. It is not compulsory for any member of staff to take part in this preparatory training.”

Phil Verster, managing director of ScotRail, previously dubbed the RMT ballot "inexplicable", stressing that there are no proposals on the table to extend driver-only or driver-controlled operations.

A spokesman for Transport Scotland said: “This is a matter for ScotRail and the unions. We encourage both parties to continue discussions with a view to resolving this issue as soon as possible so that passengers do not suffer.

“After his appointment as Transport Minister [on Wednesday], Mr Yousaf is looking forward to familiarising himself further with the industry, meeting key stakeholders and continuing to have a good relationship and regular dialogue with them."