A trade union has warned that 147 jobs could be lost at a foundry specialising in railway parts if it loses out on a contract to an overseas firm.
Unite said the entire Progress Rail Services plant in South Queensferry could be shut by the end of the year, in what it claimed would be another "massive blow" to manufacturing jobs in Scotland.
The company - which is part of the giant Caterpillar conglomerate - supplies a variety of rail products and has five sites across the UK.
But the union warned the loss of the South Queensferry operation would be another example of skilled railway work being removed from Scotland.
It said a Network Rail decision to send work overseas could lead to the site's closure.
The Record understands redundancies could start from November 30 with the dismissals following by the end of the year.
It comes after the decision by Wabtec to close its Kilmarnock factory in March, which refurbished high speed train carriages leaving around 100 workers unemployed.
Last July 200 jobs were axed when the historic Caley Rail Works in Springburn closed its doors after more than an 130 years.
Progress Rail Services acquired the South Queensferry site in 2011 and describes it as “one of the most modern steel foundries in the UK with a history of high-integrity steel casting manufacture for over 100 years”.
Unite industrial officer, Graeme Turnbull, said: "Around 150 highly skilled jobs are on the brink of being lost over the coming months, which is why we are calling on the Scottish and UK Governments to immediately initiate discussions with the company and Unite to see what measures could be brought forward to keep the site open.
"It’s depressing news to see a successful UK based manufacturer that has supported this country’s rail infrastructure for over 100 years being faced with closure.
"The loss would mean that the entire UK network would be fully dependant on imported railway components, which would be a further travesty following the closures of Wabtec and the Caley Rail works.”
A Network Rail spokesman said: “Network Rail has yet to award its new track (switches and crossings) contracts but has approached its current suppliers with the indicative outcome of its tender and bidding process.
“The vast majority of this work, around 90 percent, remains in the UK.
"Progress Rail currently has a full workload from Network Rail for at least another six months and we continue to work with them, and their US owning company Caterpillar, to manage current orders which they have accepted and are contracted to complete.”
A spokeswoman for the company said: "Progress Rail was recently notified of Network Rail’s intention to award a significant infrastructure contract to other suppliers.
"This award constitutes the majority of the volume Progress Rail has historically received from Network Rail.
"As Network Rail’s largest supplier of track components, Progress Rail is challenging the award and has notified its employees.
"Due to the potential impact of Network Rail’s tender outcome, Progress Rail has opened a collective consultation with employee representatives at each of its UK trackwork locations to discuss possible redundancies and efforts to mitigate potential impacts, although no formal decisions have been made at this time."
