The Dublin to Belfast Enterprise Service, run jointly by Northern Ireland Railways (a company operated by Translink) and Irish Rail–Iarnród Éireann (which only services the Republic of Ireland), operates trains, the fastest of which take about two hours, between Dublin and Belfast's Central Station. A single journey costs £30; a same-day return is £32. You can change trains at Central Station—which, in fact, is not that central—for the city-center Great Victoria Street Station, which is adjacent the Europa Buscentre.
Northern Ireland Railways (NIR) runs four rail routes from Belfast's Central Station: northwest to Derry via Coleraine; east to Bangor along the shore of Belfast Lough; northeast to Larne (for the P&O European ferry to Scotland); and south to Dublin. Nine daily weekday trains operate between Belfast and Derry, with seven trains on Saturday and five on Sunday. The journey time is about two hours, and a round-trip ticket costs £17.50. If you travel after 9:30 am, you'll get a third off the standard fare. Best buy: the £7 Sunday Day Tracker gives you unlimited travel on all scheduled train services within Northern Ireland.
There are frequent connections to Central Station from the city-center Great Victoria Street Station and from Botanic Station in the university area. If you want to tour the North by train, contact Translink: an iLink ticket allows unlimited travel on bus or train (£16.50 per day, or £57 per week; it costs £1 to buy the card).
Enterprise Service. Central Station, E. Bridge St., Belfast, 028/9066–6630; www.translink.co.uk/enterprise.
Iarnród Éireann. Dublin, Co. Dublin, 00353/836–6111; www.irishrail.ie.
Northern Ireland Railways. Central Station, E. Bridge St., Belfast, BT1 3PB. 028/9066–6630; www.translink.co.uk/services/ni-railways.
Botanic Station. Botanic Ave., Belfast, BT7 1JQ. 028/9089–9400.
Central Station. E. Bridge St., Belfast, BT1 3PB. 028/9089–9400; www.translink.co.uk.