More than €150m has been spent on Dart upgrade ahead of work starting

The Dart system is currently undergoing a number of extensions. Picture: Eamonn Farrell/RollingNews.ie

More than €150m has been spent on the upgrading of Dublin's rail network before work has commenced.

The Dart system is currently undergoing a number of extensions, with the first, Dart+ West, along the Maynooth line and the second, Dart+ Southwest, towards Adamstown.