A new report has concluded that extending the Western Rail Corridor from Athenry to Tuam and onto Claremorris would not provide value for money, and would do little to reduce traffic congestion.
The report was carried out by accountancy firm EY, and has been described as "fundamentally flawed" and "not fit for purpose" by the West on Track campaign.
The group claims the report is riddled with inaccuracies, and it seeks to gold plate the costs of reopening the railway while understating the benefits, in order to ensure the resultant cost-benefit analysis will be negative.
The West on Track group says it's unthinkable that such a flawed report could ever be allowed to form the basis for an informed decision on the future of this kep piece of infrastructure.
The group says the arguments for reopening the Western Rail Corridor are as valid now as they have ever been - in terms of balanced regional development.
Meanwhile, the Western Rail Trail campaign - which is campaigning for greenways along the route - says this EY report ends the Western Rail Corridor as a viable option.
Spokesman Brendan Quinn says it's now clear the line will not reopen in the next 30 or 40 years, if ever, and is calling on Mayo and Galway County Councils to follow the lead of Sligo and apply for funding to put a greenway on the line, creating jobs and amenities, and to preserve the route in case a railway is ever possible.