Double Track - North Dublin

Fourtracking the northern line is due to go to consultation and a report will be released on various options, its going to tender this summer with it being finalised at the end of August.

I suspect that Dublin will have a 2nd if not a 3rd metro line before the Northern line gets 4 tracked. Most of the benefit for 4-tracking accrues to the Enterprise - DART speeds would not be improved while DART capacity would increase by only 10% or 15%. In any cost benefit analysis this will never work - Belfast/Dublin carries about 3 or 4 thousands a day on average - there are bus routes in Dublin that carry more than that. Say - optimistically - 4 tracking could be done for 2B - spending this amount to improve journey times for 3k passengers a day will never stack up.

A new line would require an even higher level of CPO or tunnelling, which would be many times more expensive than widening the existing corridor.

We need to be realistic here on spending even 1 billion on knocking 20 minutes off a service which carries 1m passenger trips per year. The northern line is effectively dedicated to DART in terms of capacity and movement patterns as it is.

Basic rough arithmetic - 1B capital spend equates to between 50 to 100 million euro per year depending on the cost of financing formula you use. That’s 50 to 100 euro per passenger trip to save 20 minutes which is a multiple of the ticket price. Forget about spending multiple billions - it would be cheaper to offer a free helicopter service between the two cities.

Even if the time saving resulted in a doubling of ridership (and I don’t see where this new demand would come from), intercity numbers just cannot justify a spend like this when there are 200 times as many commuters in the city itself and suburbs spending an hour or more commuting every day.

Sort out being able to get around the city and its environs efficiently first, then we can start thinking about tunnels and infrastructure to improve journey times for intercity passengers.

Well yes, they don't 'require it' in the sense that a slow service can be run to them without four tracking, but if we want to provide a game changing service, then it is necessary. Even as things stand, the combined population of Navan and Drogheda on their own is 80,000, and they are at an ideal distance from Dublin for a fast commuter service. They are the sort of towns where we should be building to solve the housing crisis.

It's probably less about shaving a few minutes off and more about capacity right? Same issue that we're running into with the Rosslare situation, IÉ want to get IC's off the mainline where possible and into termini, by quading like they're doing with Dart+ West, or by terminating services outside the city, like what they want to do with Rosslare services at Greystones/Bray.If we want to get a Hourly or even hypothetically a half horuly Belfast service at peak in the future, that likely isn't going to work if we want to also run an efficient high capacity Dart+ North.

This is a real laymans drive-by-commenting here but in my experience, the Enterprise is far more often delayed in the North approaching Belfast than it is in the Dublin area.

You keep repeating this 3 million number but it's just not relevant. What's relevant is numbers in the line's catchment area AND who have a need to get to somewhere else served by the route.

We're not talking about building a service where none currently exists, we're talking about a big spend, a lot of disruption and (most annoying for me) a big diversion of resources away from far more critical issues with PT in Ireland to knock 20 minutes off a service that currently exists and is available to passengers who need it.

There is nothing "ridiculous" about the 3000/day figure - that's the ACTUAL number of average passenger journeys per day on this route according to official rail statistics. I've included a doubling of numbers in my rough CBA earlier even though I don't see where these extra passengers would come from. I could include a quadrupling and it would still look silly in terms of CBA.

There are far more pressing issues for Irish public transport. By a rough calculation, there is about 8 human life years wasted PER DAY just in terms of the difference between commute times in Dublin and the European average for a city of Dublin's size. That's nearly 3000 years of life wasted every year. This is a genuine human tragedy in my opinion. Faster intercity is a future "nice-to-have" compared to doing something to alleviate the misery of the daily commute for 100s of thousands of city dwellers across the country.

By that logic, we should stop investing a penny in every last corner of Ireland and focus solely on Dublin for the next 100years. Utterly ridiculous logic.

I mentioned 3million twice actually. You ignored the comment the first time, then proceeded to produce a rough CBA using the same 3000 daily number you already quoted. You conveniently ignored my point on Heuston Intercity patronage of 24000 per day, which cover a much larger area and distance. Clearly there's enormous untapped potential on the northern corridor.

Just to be clear, I am not suggesting a new intercity tunnel. 4 tracking, or significant sections of 4 track is the best solution, hence why they've allocated funding to access that option.

You keep mentioning 20minutes, but the AIRR suggests Belfast-Dublin journey times of 1hr 10minutes, a 50-60minute saving.

No one is suggesting doing everything all at once. You've suggested not 4 tracking the Dublin-Belfast axis until everything else is done, which is bonkers. This is a vital piece to connect the 2 largest cities in Ireland, which have historically been poorly connected - socially, culturally and politically. However this is changing very quickly.

You based your logic on current train numbers of 3000 per day which is nonsense. There are 7 daily trains in each direction between Dublin and Belfast. This compares to 21 direct trains daily between Cork, Limerick and Waterford, with additional trains on top of that to Kildare, Portlaoise, Galway etc.

The untapped potential of the northern corridor is enormous and comparing to the southern corridor is extremely relevant.

You just need to look at a population density map to see how much potential there is on this corridor.

It wouldn't double it, not unless something like the DART tunnel is built. As it is, DART+ north will provide 9 DARTs per hour peak per direction between Clongriffen and Connolly - about a 6 minute frequency. There would be no way for the system to handle a doubling of this - 18 DARTs an hour (3:20 minute headway) arriving into Connolly?

As it is currently used, the northern line is almost fully dedicated to DART - with the 3 other slots in the DART+N plan shared between commuter and the planned hourly enterprise. The commuter and enterprise services have to crawl between DARTs and match their speed (and all the stopping) - so it's the DARTs that degrade Enterprise and commuter performance, not the other way around.

And because of this, the benefits of 4 tracking would accrue to Enterprise and commuter passengers almost exclusively with at best a couple of extra hourly slots for DART. That's what makes the business case difficult and that is why, every time they've looked at it, they've found something better to do with the money.