The semi-state body is calling for a DART to Dublin Airport instead...
Irish Rail has argued that preference must be given to the construction of a DART line linking Dublin Airport to the city centre over the planned €2.4bn Metro North scheme.
The proposed DART service was sidelined by the Government last September, when it announced that it would focus instead on getting a high-speed Metro North rail link running in 12 years' time.
According to the Irish Independent, Irish Rail's director of infrastructure Don Cunningham has now made the case that space needs to be set aside at Dublin Airport for the DART line, as he forecast that "other major rail developments, including Metro North, will continue to be deferred in the context of funding constraint."
The Metro North light rail system was included in a €27bn capital spending plan for 2016-2022, though the State acknowledged that it would be over a decade before the 16.5km line was operational.
Construction is scheduled for 2021. Click here to read the full details of the Metro North plan.
Meanwhile, the alternative 7km Dart line which Irish Rail favoured at the time was estimated to come at a cost of a mere €200m.