[1] The name of the train comes from the "enterprising" approach that the GNR(I) took to make journeys more convenient for passengers despite the requirement for customs checks.

The 2 hour 15 minute timing allowed for this load and included provision for some delays en-route, such as temporary speed restrictions for track repairs.

This comprised a 10:30 departure from Belfast, returning at 17:30 from Dublin, and was hauled by one or other of the GNRI Class V 4-4-0 Compound Locomotives Nos.

[1] The next development took place in 1950, when new AEC / Park Royal Vehicles Diesel Mechanical Railcars were introduced on the Dublin-based train.

[1] Northern Ireland Railways came into existence in 1967, and shortly afterwards a complete new train was ordered for the NIR operated service.

railcars, and comprised Diesel-Electric main line locomotives and a train of eight BR MkIIb coaches, identical to the latest type entering service on British Railways, with suitable modification for the Irish Standard Gauge.

[1] In 1972 CIÉ introduced BR MkIIe air-conditioned coaches on their train, bringing the standard into line with the NIR set.

[1] The service was upgraded in September 1997 with a new timetable and new coaching stock from French train makers De Dietrich Ferroviaire (now Alstom DDF).

[citation needed] From the early 1970s until the late 1990s the service has suffered disruption, as a consequence of the Troubles, when it was regularly halted by bomb threats.

These became so frequent and caused such considerable disruption to the service that a campaigning group, the Peace Train Organisation was formed in 1989.

On Friday 21 August 2009 20 m (22 yd) of the Broadmeadow estuary viaduct, north of Malahide, collapsed, causing serious disruptions to Enterprise services.

The Enterprise underwent a face-lift during between November 2007 and early 2009, with the carriages being resprayed in silver with green livery, some of which could be seen at Translink's York Road Maintenance Depot.

The same set operated its first official passenger service after its refurbishment on Monday 16 November 2015 working the 08:00 Belfast Central (now Lanyon Place) to Dublin Connolly.

On the afternoon on 18 February 2024, IE 201 Class loco 206 and DVT 9001 visited Great Victoria Street for gauging purposes.

Over the weekend of 2-3 March 2024, all Enterprise services were diverted to Belfast Great Victoria Street due to engineering works.

Additional to a trolley service there is a "Café Bar" serving alcohol, soft drinks, tea & coffee and hot and cold snacks.

Both classes have air conditioning vents designed into the rim of the window frames and free WiFi supplied by NI Railways.

Approximately 3 minutes from every stop the computer will announce "we are now approaching (station name)" to give passengers enough time to gather their belongings before disembarking.

Since the Enterprise brand aims to be politically neutral, there are no Irish Rail or NI Railways logos inside or outside the train (with the exception of the alcohol consumption policy poster, which includes the logos of both operators), only Enterprise specific branding, all announcements are made only in English and not in Irish, and all items available for purchase are dual priced in pounds sterling as well as in euro.

Unlike IÉ's Dublin-Cork services, which operate with the locomotive operating with a generator control car that provides power for lighting and heating the train, the Enterprise fleet was only equipped with an ordinary control car, which had no power generating capability.

The second carriage in the Enterprise train set, numbered 9101–9104, is an additional First Plus coach with 47 seats (no wheelchair space or luggage area).

Both IÉ and NIR have an ambition to introduce hourly services, but it would be necessary to procure new, faster rolling stock to achieve the required improvements in frequency and speed.

In 2024, an announcement was made that funding totalling €165m had been secured from multiple sources to procure new rolling stock for Enterprise.

This new fleet will be formed of a total of eight new battery-EMU sets, intended to use the current 1.5kV overhead lines (OHLE) that is in place between Dublin Connolly and Malahide, with battery power used for the rest of the route to Belfast Grand Central.

In the event that the remainder of the route to Belfast is electrified, the batteries would be removed and the trains run wholly using the OHLE.

[10][11][12] This was reiterated in a statement by Conor Murphy, the then Northern Ireland Minister for Regional Development, who stated that the two companies had made a presentation to the North/South Ministerial Council in October 2007 putting forward the case for improvements in the frequency and speed of the service.

[7] The line south of the border was upgraded to continuous welded rail in the 1990s, while NIR has also made track improvements to allow an increase in speed.

[15] Enterprise would require a minimum of seven trains to operate an hourly service – until 2013, IÉ had a significant number of stored Mark 3 rolling stock available, of which five sets were push-pull capable.

[16] In July 2024, as part of a set of major improvements to its national timetable, Iarnród Éireann announced that Enterprise would transition to an hourly frequency following the opening of Belfast Grand Central in October 2024.

[17] In November 2007 the cross-border IBEC-CBI Joint Business Council, in a submission to the North/South Ministerial Council, stated that Enterprise was falling behind compared to the improvements of other international rail providers, with delays "often up to an hour" and serious reliability problems and an uncompetitive journey time against making the journey by road.