The hearing is expected to last for five weeks
More details about Dublin's long-awaited Metrolink are set to be revealed today.
A five-week oral hearing by An Bord Pleanála is starting this morning - 15 years on since the first one.
It'll involve discussion over how the high-capacity underground railway between Swords, Dublin airport and Charlemont in the south city centre will be built.
TII said the modern and efficient rail link will see trains running every 90 seconds and will be capable of carrying up to 20,000 passengers per hour in each direction and 53 million passengers a year.