Irish Rail has denied that time is running out for a decision to be made on Dublin's DART Underground project.

It says the Government has until next month to make a decision on the €4bn project.

However, property owners affected by compulsory purchase orders fear the plan is on the verge of collapse and that there will be years of further delay.

The High Court has imposed a deadline of 24 September for Irish Rail to activate compulsory purchase orders for the DART Underground scheme.

Otherwise its planning permission lapses

Property owners including O'Callaghan Hotels had taken the High Court action claiming that land earmarked for CPO had become subject of 'planning blight' with sites lying derelict while a decision is awaited on funding for the plan.

Another developer, Michael McCabe of Flancrest, had planning permission for 33 apartments on another site at Bridgefoot St but it lapsed as it has been tied up in the railway planning process for six years.

He cannot go ahead with a fresh planning application until plans for an evacuation shaft on the site for the underground are decided.

He says that Irish Rail needs to begin the legal process by 11 August next to activate the CPO in time for the 24 September deadline.

But both Irish Rail and the Department of Transport deny this saying the deadline is next month.

A departmental spokesperson said "a decision on the DART Underground Project will be made as part of the Government's new Capital Plan which is currently in preparation and which is expected to be announced during September".

The DART Underground is regarded as the most important transport project in the country with city centre stations at the Docklands, Pearse Street, St Stephen's Green, Christchurch and Heuston linking all national rail, dart and Luas services.

It could treble the number of rail passengers from 33m to 100m.

It would cost €4bn but half of that would be expected to come from private investment.

Meanwhile, the Phoenix Park tunnel is due to be open for passenger trains next year providing a link between Heuston and Connolly stations.

But Irish Rail says it is only a short-term solution for rail connectivity as it does not have the same capacity as the DART Underground.