TSSA general secretary Maryam Eslamdoust has backed members at Great Western Railway who are preparing to vote on possible strike action and action short of a strike.
Ballots are due to open on Thursday 22 October and close on Wednesday 11 November. The union says the disputes concern different groups of staff and have not yet resulted in a strike mandate.
In one dispute, TSSA wants shift-work flexibility allowances included in basic pay. It argues that the current arrangement affects pensionable earnings and can reduce pay during maternity and similar leave. The roles involved include staff whose work helps position trains and crews.
In a separate dispute, clerical members in the finance directorate say a reorganisation has added accounts-receivable duties without a corresponding change in grading or pay.
Indicative votes have shown support for action in both groups, according to TSSA. Eslamdoust said the union remained willing to return to talks with GWR.
The formal ballots will determine whether members authorise industrial action. No strike dates have been announced.
