High-speed trains are running every hour from Cork to Dublin for the first time today.
The weekday services between the country's largest cities will operate between 7am and 9pm as part of Irish Rail's new timetable.
The fastest journey on the Dublin-Cork route, a distance of 160 miles, will now take just under two-and-a-half hours.
Irish Rail boasts a record number of new routes due to increased investment in locomotives and recent track upgrades.
The company claims to be the European Union's fastest growing railway with more than 43 million passenger journeys in 2006 - a 14 per cent increase on 2005.
PA
