The curent length of the NIR network is 342 km (210 miles) and the company operates trains on two main routes: the line between Belfast and Londonderry, and that between Belfast and the border with the Republic of Ireland. On the later route NIR operates a joint service of fast trains between Belfast and Dublin in conjunction with the state railway company of the Republic of Ireland, Iarnród Éireann. NIR also operates a branch line from Coleraine to Portrush, and suburban services from Belfast to Bangor, Larne, and Portadown.
Northern Ireland Railways was formed in 1968 when it took over from the Ulster Transport Authority.
Until the 1950s the Northern Irish rail network had around 1500 km (900 miles) of track, but most of this has since been closed.