Dublin to Belfast Railway widening?

Pfungstadter

I thought that the Dublin - Belfast Rialway was to be widened as from Town to Howth Junction to 3 track. It was announced a few years back. There WAS the room to do it a few years ago, allot of the bridges are wide enough for 4 track. But bow I see they have constructed huge concrete ramps at most of the stations, Killester Harmonstown Raheny. And Howth Junction been redeveloped.

Was this plan quietly dropped

It was announced at the same time as the Widening of the Heuston line to 4 track

Victor

It was suggested, although to say it was "planned" might be an overstatement. Extending the DART to the airport would have made it necessary, but without the airport I'm not sure if it is justified, although there is some congestion, especially for express trains at peak times.

MarkoP11

It was in platform for change. It is obscenely expensive. If the airport line had gone ahead it would actually reduced the case for 4 tracks as it had a short 4 track section and a flyover.

On capacity terms the line can take everything planned, there are no level crossings and with good timetabling you can avoid trouble at Howth Junction. Signaling could be upgraded to 20 trains per hour, giving fast trains 2 slots. The question is can you justify 500+ million to save 5 minutes on some trains, Kildare line is different as the mix of trains is very different over a longer distance

What is important to note is the new East Wall bridge is 4 tracks wide and it would be reasonably straight forward to get 4 tracks from East Wall Junction to Killester, there is a big green space on the west side. The quick fix is a third track from Howth Junction where the new stop block is to beyond Killbarrack

SeanW

I think dynamic passing loops should be done on not only the Northern Line but all twin-lines out of the city.

Basically, that means run quad-track with trap points etc through every 3 or 4 stations. So that no matter what timetable is made up or how badly it goes wrong, an express train never has to lag behind a local for more than a couple of stops/5 miles.

Pfungstadter

The line can take everything planned cos that's all they can plan for, the present capacity on the line. I used to use the line and it seriously lacks capacity. It should be 3 track as far as killester. This will give a small bit extra capacity for commuter services to bypass dart services. Which is what messes everything up. Also theline north of Howth Junction should be widened at the new station planned north of howth junction. This would give passing loops or what ever you call them and enable the widening of the line line north of Howth Junction.

I didn't travell the line for a few years and used to be a regular user but what I saw the other day I couldn't believe. They have dug themselves into a hole with these huge concrete structures. Ok the ramps are great, nice easy slope. Dunno. Maybe they should have planned this better in the late 70's - early 80's when they were doing the DART stuff, creating island platforms from Killester to Killbarrack before the line was over subscribed.

Dunno but long term planning is the key to successful transport and saving loads of €€€€€€€€ in the long run. Doesn't seem that they are doing this with the Metro!!

found this map though

http://www.extendthedart.com/images/inter_map.jpg

dead air

Trevor Sergent also suggested this a few years back. His concern was that the Dublin/Drogheda commuter services were frequently delayed to make way for Dublin/Belfast trains. What used to happen was that northbound Drogheda commuter trains had to switch tracks to the southbound track between Skerries and Balbriggan and stop to wait until the Enterprise passed, and then switch back to the northbound track and carry on with its journey. This used to happen on a number of daily services on that route particularly in the afternoon. Although with new signalling, timetables and trains the situation has greatly improved in recent years even though it does still happen occasionally.

dowlingm

How hard is it to implement tidal flow on 3 tracks?

John R

dowlingm wrote:

How hard is it to implement tidal flow on 3 tracks?

As long as the lines are signalled for two way running it is no more difficult (and no less safe) than one way running. The DART lines are currently signalled for bi-directional running.


The capacity issue on the Northern Line is primarily a signalling issue not a raw line capacity one.

The running of non-stop and local services on the same line does mean some compromises have to be made but with a high capacity signalling system and some slick operations a good mix can be accomadated. The simple explanation is to give the express trains a small extra headway over the normal local-local train gap and slot the following local immediately behind. The compromise is that the express will not be able to reach full line speed, it means that a a few minutes extra are needed over the raw potential but it is an acceptable price overall. The key is a signalling system that allows a very small gap at low speeds which would allow a stopping train to be slotted in almost immediately behind the preceeding train.