Howth, the Midlands line and the PPT.

gjim

Fooling around with Google Earth got me thinking about post-Interconnector commuter rail in Dublin. The plan to get rid of the Docklands station makes sense with the huge increase in capacity through Connolly from the Maynooth direction which will result. This returns the Midlands line to a practically unused state. The case for using the Phoenix Park tunnel for commuters will be weakend by the existance of the Interconnector leaving another piece of infrastructure unused. Finally there's the question of what to do with the Howth branch.

Ok, so this is real crayon stuff but it looks to me like you could build a curve from the Midlands line, immediately to the east of where it crosses under the northern line to join the latter in the direction of Howth. The curve would be tight but no tighter than the one to the west heading into Connolly and the gradiant would be much less. With this curve you could run a Howth to Heuston service via the Midlands line and the PPT. This would link with the Ballbriggan to Hazlehatch DART at Howth Junction.

You could then consider building a new station/interchange with the other DART line at Ossary Road. Or build a station across from the pending redevelopment at Mountjoy supported by levies and one in Cabra near that large undeveloped area with the same idea. They could also look at building a curve to bring the terminus of the line right into Heuston rather than have it 500m away. If the frequencies on the line ever made the intersection with the Maynooth-Graystones DART at Gun's Cross bridge really problematic then they could grade separate the crossing by continuing and deeping the Midlands line tunnel there so the line went under the DART.

Brand this new service DART even if it was run on DMUs and then you could get rid of Howth as a terminus for the existing DART service without causing a war which would benefit the Balbriggan-Hazelhatch DART. I can't imagine this would cost that much initially; a couple of new curves and maybe only one station not funded by developer levies. The potential would then be there to open up a big swathe of the north inner city to rail by opening more stations along the route coupled with high density development along what would be a third pseudo-DART line.

Winters

Technically a non runner. Curves and gradient are not sufficent. With the omission of the airport spur there is no need to 'solve' the Howth spur.

The areas on the Midland line and PPT do need services though.

loyatemu

you could have a circular service: Hazelhatch-Heuston(P10)-Cabra-CrokePark-SpencerDock-Pearce-HighSt-Heuston(Underground)-Hazelhatch
and vice versa.

EDIT actually just remembered the PPT line doesn't have access to the Midland line so service would have to run through Drumcondra and would then involve taking slots away from the Maynooth-Greystones DART.

gjim

Winters wrote:

Technically a non runner. Curves and gradient are not sufficent. With the omission of the airport spur there is no need to 'solve' the Howth spur.

The areas on the Midland line and PPT do need services though.

I don't think the gradient would be an issue; there's almost as far as the East Wall road to achive the 4 meter climb - about 450m in total. The curve would be tight 'though at about 140m radius max.

I don't see any other way of utilising the Midland line and PPT. It wouldn't make any sense to run trains from Heuston to the Docklands station (which probably wont even exist at that stage) and the curve south to Connolly wouln't make sense either with the Maynooth DART in place even if it didn't suffer having the awkward bridge over the canal and the bad gradiant. Coming from Hueston, if you can't go south and you can't go east at this point, then north is the only option left.

loyatemu wrote:

you could have a circular service: Hazelhatch-Heuston(P10)-Cabra-CrokePark-SpencerDock-Pearce-HighSt-Heuston(Underground)-Hazelhatch
and vice versa.

I suspect the tunnel will be starting too far north for either the Midlands line or the Drumcondra line (for want of a better name) to have access to the Interconnector.

MarkoP11

Midland and Drumcondra lines will be connected to the tunnel, its on the plans IE submitted to DCC

Winters is quite correct the gradients down there are very very troublesome

You cant access Heuston from the Midland line, anyway if you are coming from Howth you will end up in Heuston anyway