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Unread 12-11-2012, 16:28   #8
Inniskeen
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Join Date: Oct 2010
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In simple terms level crossings traditionally interacted with signalling systems as follows.

Gates not closing across the railway

These were typically unsignalled and un-interlocked. Hundreds of such crossings still exist.

Gates closing across the railway.

Generally speaking it was necessary for the signalman controlling entry to the section containg the level crossing to contact the crossing keeper and advise that a train was about to enter the section. The crossing keeper would then close the crossing gates to road traffic. If the signalman could not make contact with the crossing keeper an approaching train would have to be cautioned to expect the gates to be closed. In addition as time progressed distant and stop signals were increasing provided at busier crossings, especially in urban areas.

At Merrion, Sydney Parade, Sandymount, Serpentine and Lansdowne Road there were signal boxes provided and the signalling was absolutely interlocked with the level crossings long before DART was even a pipe-dream. The fact that a signal may have been immediately beside a level crossing didn't necessarily mean that a train could approach that signal with the crossing gates closed. Typically a train would be allowed approach only when the gates were open for the railway and when stopped the gates could be closed again if the train was not going to proceed immediately. Pretty much the same applies today except that the signals and level crossings are are centrally monitored.

Merrion may well have been struck by trains in the steam era but it was certainly not routine and would have been the subject of at least a company inquiry. Similar to a SPAD these days. I wouldn't describe SPADS as routine but they do happen.

No issue with a 15 minute interval DART service, but the current journey time severely impacts on other services and needs to be improved. Ideally Rosslare trains would depart Connolly just ahead of a DART, serve Pearse and Dun Laoghaire and arrive in Bray just behind the previous DART without being delayed by it. Journey time for the diesel 25 minutes, for the DART 38 minutes. This or something similar worked reasonably well for at least fifteen years until DART journey times were extended. The problem for Rosslare trains was subsequently further compounded by the regular interval Greystones service and the removal of infrastructure at Dun Laoghaire.

It is the 30 minute interval Greystones service that is incompatible with a reasonable journey time for Rosslare services to/from Greystones, not the 15 minute interval Bray service. Probably could be sorted if there was a will to do so.

Last edited by Inniskeen : 12-11-2012 at 16:37.
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