Quote:
Originally Posted by sean
As to the matter of train speeds, it could be better - by a good margin - but all the lines ex-Connolly have the disadvantage of being twin-track mainlines with a small amount of Intercity traffic mixed with a lot of short haul commuter traffic. Whereas with Heuston, the mainline out of that carries 2/3 or so of all national Intercity traffic plus requirements for a frequent short haul commuter service to Hazelhatch and Kildare. Hence it was a much more obvious candidate for the quad track treatment that allowed more efficient line-sharing. Both the Rosslare and Belfast lines are worse off on this score, sharing the last few kilometres of the run into Connolly with the DART.
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Not sure that the Cork line was the more obvious candidate for quad tracking especially in the context of existing requirements as opposed to potential future requirements. Having said that, Irish Rail were correct to specify quad tracking in the context of planned additional stations between Inchicore and Hazelhatch. As it turns out one of these massive stations hasn't even opened while the remaing intermediate stations between Hazelhatch and Heuston are little busier than Campile was before closure.
Meanwhile, post DART interconnector, Irish Rail fantasise about running 19 trains per direction per hour on the double track between East Wall Junction and Clongriffin. This is almost twice the current busiest hourly rate and approximately equal to the current
daily utilisation of the slow lines between Cherry Orchard and Hazelhatch. It is utterly impractical and would effectively render the northern line irrelevant to all but short haul commuters.
In my experience the quad tracking on the Cork line sees comparatively few overtaking movements. In the outbound direction there is only one scheduled overtaking movement on Mondays to Saturdays and two on Sundays. The train overtaken in each instance is the 1855 from Heuston and the overtaking services are the 1900 to Cork (daily) and 1905 Tralee (Sundays).
The inbound direction is a little more used with 5 trains being overtaken Monday to Friday, 4 on Saturday and two on Sunday. One of these trains, the 0743 from Portlaoise is overtaken by two services, the 0615 from Cork and 0635 from Galway.
The last trip I made out of Heuston saw the 1030 from Cork stationary on the fast line at Cherry Orchard to allow the late running and lighly loaded 1230 ex Newbridge run ahead of it. Not exactly inspiring and not particularly unusual either.
In conrast to the Cork line the northern line currently requires quad tracking as almost every non-DART service suffers a journey time penalty of anything up to twenty minutes due to a combination of inadequate track capacity, poor scheduling, poor traffic management and the very low average speed of DART services.