Navan Rail Line

In a perfect world that route would probably work best, but new alignments are an easy way to make costs spiral and delay the project further. Considering it already isn't due to open for another 11 years, I think the simplest option would be best.

We went nuts because we had a 3rd world road network...I remember the days of it taking 6 hours to get from Dublin to Galway. It was shocking.

We do future proofing extremely poorly in this country so I would say yes...all the main national roads leading into Dublin should be motorway standard...but I accept that it is under capacity and probably will be for some time.

I always thought Kilbride as a location was ripe for serious development....

I don't see why Trim would be a better candidate for rail services than Dunshaughlin. Dunshaughlin would be much easier served and Ratoath could be served at the same time (see route from @OisinCooke). I also don't believe reinstating the old alignment as far as Kilmessan or beyond will be easy as some think. That you need to look at spurs due to >20km of serving nothing shows the fallacy of the old alignment.

Regarding a Dunshaughlin station, P&R shouldn't be a consideration. Dunshaughlin is big enough to warrant a station and a station there should be accessed by public/active transport to the greatest extent possible. If the rail line serves Dunshaughlin, it likely has to run along the M3 which allows scope for a proper P&R. A P&R at Gallows Cross (J7) would be better for serving the wider rural area between Dunshaughlin and Navan. So a new alignment not only serves existing towns, it has the potential for further P&R.

If a new alignment via Dunshaughlin was selected, crossing of the M3 could happen at the existing south toll plaza. There are already plans to move to completely barrier-free tolling so much of the space for the existing toll plaza would be available. Build a rail bridge over the M3 there and then follow the suggested route (which I've been saying for years). The old alignment requires crossing the link road into Navan from J8, that would be a major job so the idea that some (not you) promote about the ease of reinstating the old alignment is wishful thinking. Even the M3 underpass approach on both sides is lined by houses so the benefits of it are overstated.

Here is the hidden Boyne Viaduct. Can't see any reason why there would be significant risk in using it, the Victorian engineers built to last, even built for 2 tracks. Plenty of other bridges still in place. Greatly speeds construction, reduces cost and risk and reduces risk of environmental impact.

Fantasy routings with crayons are all great, but you need to consider the geography as well. There will be minor deviations but wild routings across the M3 have been ruled out.

not great but not a big deal either.
unless we are building separate lines to each of the main towns in meath off from cloncilla or wherever then really this would be the only option to serve them by rail and i do feel they need to be served or at least the majority of them.
to be honest i would forget about the maynooth/adams town link, i can guarantee it won't happen or we won't be alive to see it.
but i take your point all the same.

The more I think about, the cooler I feel towards Navan rail.

There's too much discussion here about possible alignments ignoring the elephant in the room - how may passengers can we expect to use such a service?

This is of course hypothetical but we can use the gravity demand model to get some sort of ballpark number. For example, according to the last rail census, Greystones has an average daily passengers alighting of less than 2,000. Now Navan is (roughly) twice as far as Greystones - which would mean - all other things being equal - that the demand is likely a quarter that of Greystones (demand generally falls with the square of the distance). Navan has a slightly bigger population so say that might boost the numbers by 10 or 20%.

But whatever way you look at it, carrying 1,000 passengers a day would represent a massive success and would be significantly more than you could expect based on demand modeling even with decades of population growth.

Now the NTA have suggested a figure of about €3 billion. That means spending €3 million capital per expected passenger. That's insane. Even doubling that number by adding passengers from Dunshaughlin or other stops doesn't bring the number even near €1 million per passenger?

If it wasn't for the fact that at one time in history there was a rail line, I don't think for a minute that Navan would be on the list of next obvious things to do.

Look at the distances involved - we're talking building a new alignment to a town as far away from Dublin as Drogheda is - the very outer limits of "commutable" (involving 2 hours a day commuting). Compared to the rest of the DART+ network, it's about 3 or 4 times further from the M50 than Celbridge or Maynooth - the furthest extent of DART+ SW and DART+ W. Completely lopsided for a branch line.

I'd like places like Navan (and those championing the gombeenist WRC extension) to first earn the right to a rail link.

For example, given the very low AADT numbers for the M3, I don't see any reason why a bus/coach synchronized with train arrivals and departures from M3 Parkway couldn't reliably and consistently get you from Navan to the M3 Parkway in 25 minutes - likely as fast or faster than any stopping train.

If this service were in place Navan to Connolly would be about an hour and a bit. This is roughly what the rail link promises - so the demand of a service like this would provide some indication of the demand for a rail-only service.

If a service like this is insufficient to cope with demand, then by all means consider rail as an upgrade.

If we're going to build 30km of new electrified alignment starting at the M3 Parkway, then Drogheda would be a far better target for the end of it - you could send express commuters and inter-cities into Dublin that way instead of competing with DARTs on the Northern coastal. Even the 4,000 passengers a day from Belfast would mean that such an alignment would be much more utilized than a Navan link.