In the Independent today, Foreign Affairs Minister Charlie Flanagan floats the idea of a 60-minute Belfast-Dublin railway journey as a possible outcome of a brexit deal. This is an interesting, and indeed exciting, idea but I wonder if the Minister is aware of the size and scale of the project he is proposing.

The current Belfast-Dublin railway line, whose construction began almost 200 years ago, was designed in an era when railway vehicles could not move quickly, when railways were assembled by different companies at different stages, when it was more important to connect large population centres with small villages and towns, and when carrying freight, including livestock, was a major priority.

When the Enteprise service was first introduced in 1947 (a commercial response by the then privately-run Great Northern Railway to a plan by Aer Lingus to offer Belfast-Dublin flights) it offered a non-stop time of 2 hours and 15 minutes. Gradually, over time, the GNR’s successors added stops and improved track and timings. The record timetabled journey time was reached briefly in late 1999, following the upgrade of the Belfast Central-Central Junction (near Great Victoria Street) section, when the 0800 weekday service was scheduled to arrive in Dublin at 0945, a 1hr45 minute trip, stopping only at Portadown. Since then the service has slipped somewhat; the same journey now takes 20 minutes longer, albeit with stops in Newry and Dundalk.

Over the past 15 or so years, the Enterprise service has received progressively less attention on either side of the border, especially following the upgrade of the motorway along which buses can travel between Belfast city centre and Dublin Airport in less than two hours. While the train itself is capable of 90mph running, inferior track conditions at many points along the route, especially north of the border, require the train to run at lower speeds for safety reasons. In addition, over the same period, the Dublin-Malahide section has seen the increased frequency of the DART, Dublin’s high-frequency commuter train service. Successive Irish governments have prioritised DART and suburban rail timekeeping and frequency, understandably enough given the number of voters who use the service within Dublin’s commuter belt; but this has come at a cost to the Enterprise, which often finds itself running directly behind a stopping DART service, especially travelling south. This has to be accounted for in the timetable.

Even if the track were brought up to spec and the DART problem solved, it is hard to see how the service could be improved beyond the 1 hour 30 minute schedule envisioned by the Enterprise renewal project of the early 1990s. The route is approximately 120 miles in length, and a 90 minute trip would require an average speed of 75mph, significantly above today’s fastest average speed of 50mph. Charlie’s vision of a 60-minute trip would require an average of 120mph, well over double the present speeds. No trains in Ireland today are capable of operating at this speed.

This is significantly faster than the journey time by rail between the UK’s largest cities. The London-Birmingham journey, which is roughly the same length, takes 1hr13 minutes by express, using track and trains rated for 125mph running. To deliver the timetable Charlie is talking about would require doing the same thing the UK is doing for London-Birmingham – building a completely new, electrified high speed railway line. The cost of doing this would be considerable to say the least. It cost the UK £5bn to build High Speed 1 (excluding the refurbishment of St Pancras), a line just over half the length of the Belfast-Dublin line. Even if a way could be found to substantially slash these costs, we’re still talking about many £billions to build a railway servicing population centres much smaller than those served at the terminii of high speed rail services in the UK. It is hard to see how this kind of expenditure could be justified.

The underinvestment in the cross-border railway during the course of the past ten years gives me pause to wonder if the Irish government are in any way serious about the kind of idea that Charlie Flanagan is floating here. If they are, though, significant improvements are possible without this kind of outlay. The recently refurbished Enterprise rolling stock is entirely adequate and the issues with locomotive reliability have recently, though belatedly, been solved. The Governments should turn their attention to track refurbishment, service frequency, and the bottlenecks in the Dublin area. A simple solution, killing many birds with one stone, would be to have an hourly Enterprise service terminate at a new station in Dublin airport, with regular DART connections to the city. A 90-minute stopping service to the airport is deliverable, would easily compete with the motorway, and would offer the prospect of a major improvement in transport connectivity across the entire island.