1940s - 1960s

At 10.30am on August 11, the inaugural Enterprise service travelled from Belfast Great Victoria Street Station to Dublin Amiens Street Station (renamed Dublin Connolly in 1966).

Operated by the Great Northern Railway (Ireland), it was a non-stop prestige express service with customs checks at either end (rather than at the previous mid-points of Goraghwood and Dundalk) - running Monday – Saturday with journey time 2¼ hours.

A seven-carriage steam train aimed mostly at the business traveller, with first class accommodation, catering, more leg room and lavatories.

The 1st year in service consisted of one train in each direction – the 10.30 ex Belfast and 17.30 ex Dublin.

The new service was usually worked by locomotives named Eagle, Falcon, Merlin, Peregrine and Kestrel – birds of prey – and painted blue.

On 31 May, a Dublin-based train was introduced for a 09.30 ex Dublin and a 17.15 ex Belfast.

5 new locomotives built mainly for Enterprise took over the service and were named after rivers across the network – Liffey, Boyne, Lagan, Foyle and Erne.

AEC Diesel Railcars replaced steam on the lightly-trafficked Dublin-based Enterprise.

From 2 October 1950, the Belfast-based Enterprise was extended to Cork with journey times of 6.25-6.5 hours.

Coaches from GNR and from Córas Iompair Éireann (CIÉ) worked on alternate days and both trains had GNR Buffet Cars at first.

This extended service to Cork ended on 27 June 1953 but a through coach continued to operate until September 1953.

On September 1 1953, the governments of the Republic of Ireland and Northern Ireland nationalised the GNR as the Great Northern Railway Board GNRB.

The Great Northern Railway Board ordered more powerful BUT diesel mechanical railcars, ending steam traction on the Enterprise. They could run up to 8 cars including a full buffet car and replaced steam on the Belfast-based Enterprise from 19 June 1957.

The GNR Board was dissolved on 1 October 1958 and its assets and liabilities were split between Córas Iompair Éireann (CIÉ) and the Ulster Transport Authority (UTA) — the predecessors of Iarnród Éireann and Northern Ireland Railways respectively.

UTA took over the northern portion of the route and CIE took over the southern portion.

1st intermediate stop introduced at Dundalk, open to Belfast-bound passengers.

Enterprise service doubled to 4 trains each way per day and Portadown stop was added.

NI Railways was established in 1967 and, from January 1969, the NIR Enterprise was worked by new 70 class diesel-electric railcars.