Great Western Railway staff have voted to strike over pay, pensions and flexible working, threatening disruption to services connecting London Paddington with the South West, Wales and the South. No dates have yet been set for walkouts.

The dispute involves members of the Transport Salaried Staffs Association (TSSA) working in areas including rostering, service delivery and performance strategy. The union said separate ballots across different parts of the business showed strong support for strikes and action short of a strike.

TSSA general secretary Maryam Eslamdoust warned that both forms of industrial action would affect services unless GWR addressed members’ demands. Her concerns extend beyond pay rates: she argued that shift workers should not suffer financial hardship for working patterns that, she said, carry increased risks to physical and mental health.

For clerical staff, Eslamdoust said growing workloads should be reflected in their grading and pay. She described industrial action as a last resort and said the union remained ready to negotiate.

“We stand ready to get back around the table and talk at any time,” she said.

GWR said it was seeking a settlement. A spokesperson said: “We continue to work with colleagues and their trades union representatives to find a mutually beneficial solution to the dispute and avoid damaging strike action.”

The vote creates a further risk of disruption for London passengers alongside a separate programme of Tube strikes announced by the National Union of Rail, Maritime and Transport Workers (RMT). That dispute is with Transport for London over a proposed voluntary four-day week for Tube drivers, distinct from the issues behind the GWR ballot.

The RMT’s announced walkout dates are Thursday 26 November; Thursday 17 and Saturday 19 December; Monday 4 and Wednesday 6 January; and Wednesday 17, Tuesday 23 and Thursday 25 February.

For passengers planning journeys, the distinction is important: Tube strike dates have been announced, while the timing of any GWR action remains unresolved. Both GWR and the TSSA have expressed willingness to pursue talks.