The Mini-CTC (Central Traffic Control) project is designed to introduce "power" signalling on four inter-city lines, with connections to Central Traffic Control at Dublin's Connolly Station.
The system, using colour signals similar to traffic lights, already exists on the Dublin suburban network and on the lines from Dublin to Cork, Limerick, and Belfast. The lines being upgraded are Dublin to Waterford, Tralee, Galway and Sligo, which continue to use the old "semaphore," or mechanical arm-signalling system.
With the exception of the Dublin-Sligo line, the work does not involve the entire routes. The Dublin-Ballinasloe section of the Galway line, for example, was upgraded to light-signalling in the original CTC project in the 1980s.
The Mini-CTC involves laying some 900 km of fibre-optic cables.
In line with the recommendations of the IRMS rail safety audit of 1998, trenches for the fibre-optic cables are being hand-dug, whereas the original plan foresaw mostly mechanical laying of cables. But the consultants feared this might have a destabilising effect on rail lines.
