>>1246710The main limiting factor with the Enterprise service is down to the rolling stock and the track.
The name of the service is the oldest surviving one in the UK and Ireland, and I think is older than the "Flying Scotsman" by a number of years. The Enterprise was predominantly just a loco hauled service between the two cities, and until the most recent rolling stock was brought in the 1990s.
Before that it was just an EMD JT22 loco hauling a set of Mk.3 carriages modified for Irish Gauge. Before that it was a steam locomotive hauling Mk.2s and so on.
The 90s was when a set of De Dietrich coaches and EMD JT42s were delivered to replace the existing NIR stock and make it a true international train service.
Funding for the new Enterprise came predominantly from the European Union which was keen to strengthen the ties between NI and Ireland. The De Dietrich coaches were outfitted with an almost identical interior to that of the Class 373 Eurostar, and the signage inside the Enterprise was in English, Irish, French, German and Italian. With that said, the trains were slow, only really topping out at 90mph on a section of double track in Co. Armagh around Newry.