About 100 jobs are threatened with the proposed closure of a train carriage refurbishment factory in East Ayrshire, a union has claimed.
Unite said Wabtec planned to consolidate its operations in Doncaster, South Yorkshire, citing a reduction in orders for its decision.
The union claimed Wabtec's order books had been full in recent years.
It said orders included a refurbishment contract worth about £8m funded by the Scottish government in 2017.
The Kilmarnock site, which originally opened as an engineering workshop in 1840, has helped refurbish recent Abellio ScotRail and ScotRail models.
Unite has written to Wabtec, asking the company to postpone any decision "until all avenues have been explored to keep the rail yard open".
Unite regional industrial officer Paul Bennett said: "It was only recently Wabtec was saying that was it fully committed to the long-term success of its Kilmarnock facility and that it planned to ‘invest accordingly’.
"We are dismayed by this decision and believe it to be completely premature.
"That's why we are demanding that the company work with us to explore every avenue to bring in more work.
"Unite is also asking the Scottish government to offer every support it can to keep the yard open in order to ensure that jobs can be supported in Kilmarnock and that some manufacturing footprint for our rail industry is still left in Scotland.”
BBC Scotland has approached Wabtec for comment.