double tracking in Ireland

Temp101 wrote: »

most singling was done in the late 1920's and early 1930's to save money on track maintenance, although the newly installed additional signalling equipment can't have been too cheap.

A lot of the Northern Irish singling was done more recently. Antrim to Ballymena was double track until around 1990 and Monkstown Junction to Antrim was double track until c.2001. Kilroot to Whitehead was 'temporary' singled in the 1990s but never reinstated.

The increase in rail travel in the region means, however, that redoubling is now proposed for the Derry line sections.

Hungerford wrote: »

Actually, the entire line was doubled by 1915 but they left single track through Dun Laoghaire station for reasons which I cannot remember.

Indeed, the terminus, with its fine train shed, seems to have been perceived as the important part of the station at Dun Laoghaire (or should I say Kingstown)? The line on to Dalkey seems to have been relatively poorly provided for. The single through track started at the Dublin end of the station, and ended just beyond the "Hole In The Wall" - the junction for the Pier branch. I would suggest that breaking the rock, with the attendant impact on adjacent roads etc., was a good reason for putting the doubling work on the long finger, especially as it was next door to the Corporation offices and Town Hall. To judge from "Irish Railway News" (good work RPSI putting these up!) one reason the bottleneck was finally done was because it was perceived to be impeding tourist traffic via the Pier.

Your point on NI singling being later is well made also. The Monkstown - Antrim re-opening was done in such a fashion as to make it expensive to re-instate double track. Cost saving also unfortunately applied to the Cross-Harbour project, but I suppose we should be grateful the lines are open at all, given the circumstances.

Here's a map that shows the state of double tracking accross Ireland (and Britain). It's a bit optimistic about the chances of Navan-Dunboyne and Athenry-Claremorris reopening.