High speed rail... feasibility study... maybe
 

From the proposed deal to restore Stormont
https://sluggerotoole.com/2020/01/10...mont-deal-tbc/

Good news for Parsons or whichever consulting shop gets the contract to write that study to fill shelves and attract dust

Is there any practical possibility of getting current lines to 240km/h?

Because that would be a lot cheaper and still make Cork-Belfast possible in c. 2 hours.

Of course you still have to get across Dublin and that is where the real expense would lie.

I can't imagine there's enough demand for a greenfield line to the north and west of Dublin. Could there be enough demand for Cork/Limerick/Galway-Dublin Airport to make this a possibility? Most people would be traveling Cork-Dublin or Belfast-Dublin, not Cork-Belfast or even Cork-Drogheda or Belfast-Limerick. And we know the interconnector, whatever its status hasn't been planned for InterCity trains.

It's interesting that high speed rail comes up for discussion as the UK is leaving the EU. A cross border route between two member states would qualify for EU funding. A cross border route to a non-EU country wouldn't, though I'm sure some funding could be wrangled under the heading of "peace process".

Has anyone even thought about whether this would be a new route, or upgrading the existing lines? Upgrading would have the advantage that other services could take advantage of the higher speed tracks, and would probably be less costly, but would have the downside that high speed could get stuck behind slower service, delays could arise.

The rollout of high speed lines in Spain would be worth analysing. Some of their lines have quite low population density, and it's hard to see them ever being viable without massive government subsidy.

There is an election coming

Dublin Belfast is underserved it should have double if not triple the current demand, but due to the long dragged out peace process and now Brexit the uncertainty is killing it. You could justify electrification but only in conjunction with commuter services.

Dublin Cork does well but bear in mind some sections of the line see only a train an hour in each direction (Limerick Junc - Mallow)

Neither route has air competition so the end to end time is not critical, you could start with

1. Tunnel from Killester to Airport to Rush And Lusk (shared with all trains from Drogheda/Dundalk)
2. Enhancements to 200-225kph + selective 4 track/dynamic loops around stations
3. Diversion around Armagh to address the long standing routing of the Dublin Belfast route
4. Some 4 tracking into Belfast
5. Cut stops down to bare minimum Connolly, Airport, Dundalk, Newry, Belfast
6. 75 minute end to end.

Dublin Cork, if you could deal with the Curragh and Portarlington 200-225kph would be possible across almost the entire route, no need for a new line as there is little traffic on the current. Add in electrification and you would see a serious speed up

Mark: I would agree with much of what you say.

Dublin-Belfast through traffic is relatively low and hourly services are a pipe-dream, without the extensive capacity-enhancing measures you mention. Long-distance travel on the Cork line is far greater.

On the Belfast line, I think you mean diversion around Portadown rather than Armagh. Also there is a pretty unavoidable severe speed restriction at Drogheda, and the track curvature over a lot of the line from the border to Portadown restricts speeds quite significactly.

A proper high carbon tax should enhance the competitiveness of rail over road and also vastly enhance the attraction of electrification. After all we aim to electrify private car transport, which is quite a tall order.

I think the alternate Northern line via airport is interesting, but you know politicians would interfere and insist stops be inserted to serve their communities, and we'd end up with two routes that fast trains get held up behind slow stopping services on.

I still think 4 tracking the existing Connolly-Malahide route would be to most cost effective solution. I think there are parts that would be tricky, but most are achievable. The sections in cuttings should be possible to widen by replacing the gently sloping cutting sides with concrete walls. Unfortunately, during the DART upgrade, no consideration of future widening was given, and I think all of the north side stations would need to be rebuilt. There were also a number of developments allowed close to the railway during the Celtic Tiger years, and some of those may have to be demolished to allow it. I still think this would be cheaper than a new route with a lot of tunnelling.

While there is no competition from air travel on these routes, the motorways is the main competition. It's not really cheaper or faster to go by train, so there's not a lot of incentive to take the train. The only advantage the train has at the moment is comfort, and at peak times between Connolly and Drogheda, that's very questionable.

If there was a true high speed service, and if the cost of making the journey by car reflected the impact on the environment, the train would become a lot more attractive, both in time and expense.

Operationally, I think two trains per hour to Belfast would immediately be viable, one non-stop, perhaps taking about an hour, and a stopping service retaining the current 4 intermediate stops, maybe taking 80 minuts. This could perhaps increase to 3-4 trains per hour in the future.

I don't know the Cork route as well, but it seems to be well subscribed with the currently hourly service, so I think a high-speed route could sustain higher frequency service. The high speed line could also allow improved journey times on other routes sharing the high speed parts of the line.

I would agree that a Drogheda Enterprise stop makes sense unless the bridge is twinned (seems unlikely), and I doubt local politicians would sit still for it being dropped even if it was.

As for Connolly-Malahide, 3 tracking as much as possible should be urgently pursued to allow some routing of Enterprise and suburbans around Taras and DARTs - my recollection is that 4 might be hard to get in the space available