But the exchequer is currently clawing back �25m of profit from NIR, to protect the public sector spending figures.

Many NIR trains worn out

NIR is short of modern rolling stock and large gaps often occur in its timetable.

Many carriages and locomotives have had to be scrapped because, after more than 30 years continuous service, they are worn out.

To complicate matters further, if the Northern Ireland Assembly returns to Stormont, it will be MLA Peter Robinson - the minister responsible for railways - who will make the final decisions.

Ironically, as an MP, he is also part of the committee which will report to Westminster on NIR in due course.

�180m needed

The visit by the committee will come just a month after a controversial report claimed the government must spend �183m over the next decade to keep Northern Ireland's railway system safe and viable.

The report, commissioned by the rail and bus operator Translink, called on the government to approve plans to upgrade services.

The report said �72m needed to be spent replacing trains, �67m on relaying track and replacing six bridges and redesigning and repairing sea defences.

It added that �25.5m should be spent modernising warning systems and signalling at Castlerock, County Londonderry and Portrush, County Antrim and on the closure and upgrading of some crossings.

�10.8m needed to be spent on staffing.

A special review task force has already been set up by Northern Ireland Office minister Adam Ingram to decide if it is worth spending money to bring the railway system up-to-date.