DART+ (DART Expansion)

Article mentions that there were six scheduled openings a year, which now don't happen.

Waterways gave eight times for 2025.

Marine Notice No 19 of 2025

As for rail use, very infrequent. Even the one remaining Sligo service that skips Drumcondra actually goes through Drumcondra most if not all of the time. I was last on it when a Docklands originating service encountered a track blockage and had to reverse back in to Connolly, possibly in 2018 or 19.

As it would have to be double-tracked, some change would be needed but the challenges are significant.

Rising the railway earlier is constrained by Newcommen Bridge, and the tight curve meaning it can't be much further east. I hadn't considered the sewer but that is another issue. The engineering issues are significant.

On the other hand, the only other way to get the suggested type of dedicated through running is through Dart Underground.

So you're saying only 3 trains per hour will go to Connolly on the DART+West line and everything else (7 trains per hour) goes to Spencer Dock?

I totally understand the logic of why, but just a bit of a pity for those living or working around Drumcondra. Though then Glasnevin isn’t exactly a million miles away either.

One thing to consider is that because Glasnevin is going to be such a major interchange, there may be more bus services to it than there already is planned with BC. Such as another Orbital (N1 or something) along Whitworth and Clonliffe Rd.

I think it is going to be tricky but not definitely not impossible. Most of the network would be just fine, there are just a few pinch points to deal with.

Reading about them it does sound like the S-Train network will need a completely separate system from the rest of the heavy rail network? though I don’t think the lines need to be separated like many modern metros are? So at least in theory DU is required. If so I think that means we need 4N, the express Clongriffin-Drogheda Alignment, and the Maynooth-Adamstown link. This would allow for automated lines as far as HH, Maynooth, Navan, Drogheda, and Greystones as they wouldn't need to share tracks with IC or regional services.

However I do see things getting difficult with the non-D+ extensions and the Howth Branch.

DART to Sallins and Naas is awkward but I see two simple options. Either the DART ends at HH or extend the DART all the way to Portarlington. In the former HH-Portarlington would have outer commuter services using the fast line from HH to Heuston. The later would be an all-stops Portarlington-Heuston/PPT DART using the slow-line, as I doubt the DART could use the fast line with IC/regional services if its automated. Distance wise it would be quite a long way, but time wise it wouldn't even be the longest DART to CC. I think it just becomes a question of if frequency or journey time is prioritised.

DART to Wicklow is similar. Either end the DART at Greystones or all Wexford shuttles have to terminate at Wicklow. The main issue I see is timing the Wexford Shuttle as an autonomous train isn't going wait if the Wexford service is delayed. So, to keep DART to Wicklow I think you would want most/all Greystones DARTs extended, so missing a connection isn’t too bad. Which to be fair it would be easier to extend them with a fully automated services (I think 2tph would already be possible). Also, the last 8 LCs between Greystones and Wicklow would need to be closed, but that is a small investment in comparison.

DART to Kilcock is a bit more difficult as I believe it would need some new track. I believe the depot now confirmed to be west of Kilcock, so the DART has to go that far. But you aren’t getting 4 tracks through Kilcock so Sligo line services will need a new alignment around it and/or the Adamstown link needs to start west of the depot. I think the best option would be to start the link west of the depot and build a new station at the junction to allow for a DART interchange. Compared to the other extensions it’s more infrastructure to add, but it would be worth the increased frequency/capacity.

The Howth branch on the other hand is where the problems start. I believe with 4N the slow lines would have the be the western two. Even post DU I think it’s likely the portal will be west of the line as the design of SD is no longer compatible with DU. I am not sure if it would be possible to get automated trains between a depot and the branch. However as it would still be connected to the main network through the fast lines, the best option may just be to have Howth operate with a few regular sets.

It’s safe to say the general consensus is that after DU, the DART will operate as two metro-like lines in an ‘X’ formation - Hazelhatch to Drogheda and Maynooth/Navan to Greystones. There are however, as some of you have mentioned above, definitely some kinks to iron out.

I think there are some easy solutions, but three key pieces of infrastructure are required to compliment the tunnel and allow a metro-style service: FourNorth, a Maynooth - Adamstown link, and I believe, grade separation of Glasnevin junction.

FourNorth is required. DARTs need a separate alignment from Drogheda all the way to the tunnel. Clontarf Golf Club/Killester (where the tunnel will most realistically emerge) to Clongriffin (where the fast line to Drogheda will split off) will need to be quad tracked but that’s only about 4.5/5km.

Clontarf Road station can be moved underground, so that Enterprise and outer commuter services can use the existing two tracks through Fairview and over the Tolka as the “fast lines” straight into platforms 1 through 4 at Connolly.

Next, for Maynooth/Navan DARTs to operate at their highest possible frequency, a Maynooth - Adamstown link is required. This will allow trains from Sligo Line to join the fast lines into Heuston, freeing up all track capacity on the western line for DARTs. Ideally all junctions will be grade separated but I think at the minimum, the one with the SW fast lines needs to be.

As @PlatformNine mentions though, the link line emerging after Maynooth means that with DARTs extending to Kilcock, and requiring depot access, they will still be sharing track. The link line therefore may need to go from Kilcock - or a new interchange station west of there - to Hazelhatch (or somewhere on the proposed Hazelhatch - Portarlington bypass route). The DARTs that ran to Kilcock (presumably slightly less than will go to Maynooth) can be timed to meet the Sligo train so that access to Maynooth is still seamless, but I truly believe a direct connection from the Sligo line to Maynooth is not necessary.

Finally I believe that Glasnevin Jnct should be grade separated. The section of track from the PPT to the Canal line can (relatively) easily be lowered to pass beneath the Broombridge to Drumcondra section, as it is at a lower grade already rising out of the PPT. This will create a fully grade separated line from Spencer Dock to the SW lines at Heuston.

The PPT line should then join the fast lines at Islandbridge Jnct (the only lines at that stage, as DU is still in a tunnel) to Hazelhatch, where the Kildare bypass route will split off.

This will allow all outer commuter services to Portlaoise, Carlow, and Mullingar/Longford to operate ‘semi-fast’ into/out of Spencer Dock as follows:

Portlaoise and Carlow outer commuter services will serve Monasterevin, Kildare, Newbridge, and Sallins on the existing route as the “slow lines”, and join the fast lines at Hazelhatch where they join from the bypass. Outer commuter services from Longford will operate similarly, using the Sligo Line - Heuston Line link to join the fast lines, with all services running fast to Islandbridge Jnct, where they will branch into the PPT and run slow again serving Heuston West, Cabra, and Glasnevin, before terminating at Spencer Dock.

All Maynooth/M3 - Greystones DARTs can use the line through Drumcondra and platforms 5, 6, and 7 at Connolly, while half hourly Enterprise and northern outer commuter services use platforms 1 through 4. Heuston remains an intercity only station (underground DART platforms excluded obviously), and Spencer Dock serves as an outer commuter terminus station, with an onward travel link with DU to the city centre.

This solves most of the issues while also keeping a regular service on the PPT line and completely separates all routes at Connolly. The only potential issue is at Islandbridge where the PPT line joins the gullet at grade, but this is essentially no different from say, the line from platform 7 joining the line from platform 2 “at grade” so theoretically isn’t an issue. The outer commuters using them shouldn’t be too frequent either so I see it working well.

If I’m missing anything let me know, but I’ve just been thinking that having Western and South Western outer commuters stay out of Heuston use the PPT and Spencer Dock is a good way to use the line, and to give Heuston as much capacity for intercity trains as possible, while also not crossing service paths at Connolly either. Any thoughts?

You’re right, it is a bit dicey… It would need a closure of the line and a rebuild of the canal line platforms at Glasnevin to be at a lower level, so maybe not the most attractive idea to tear up essentially brand new infrastructure…

Even with trains crossing at grade as they do presently, it is still doable, with only 2-3 trains per hour max that would need to do it, it could be worked in.

In terms of this, again I think you’re right, realistically the link will go from Maynooth, and Maynooth DARTs (8 per hour at max current driver-controlled levels) can be pathed to leave a longer gap for Sligo and Longford services. I just think it would be more feasible and definitely cheaper to build the link to the west of Maynooth, even the west of Kilcock, and have passengers transfer.

The link at present will most likely have to be almost entirely in a tunnel to avoid the Castletown Demesne, so could prove to be quite costly. Build it just a few km west of Maynooth and the price drops significantly, with a surface level alignment through what is largely open greenfield sites now possible.

Sligo and outer western commuter services could share tracks with the few infrequent DARTs that serve Kilcock and then a small transfer station could be built for passengers to transfer to a Maynooth train. If DART transfers are frequent and have a regular service, people would forget about it quickly enough I believe. The site could also be developed for transit oriented development, as a West Maynooth, and serve its own purpose outside of just a transfer station.

I agree that its ideal for Sligo trains to serve Maynooth and I absolutely realise that there are many passengers that get on or off at Maynooth, I just think that it’s not the biggest deal in the world for them to change trains out west of the town for a 5-10 minute DART hop into Maynooth. It would also save all track capacity at Maynooth to be used for DARTs allowing automation to hyper-frequent running.

If the link line is built east of Maynooth though, which I agree, and as you all say is the more likely result, then at the very least Maynooth needs two more platforms (potentially terminating ones) and the link needs a grade separated junction with the western line.

This is going way beyond DART+ (again)...