Iarnród Éireann is to increase its use of two-carriage DART trains at off-peak times to reduce fuel costs.

The move is part of a range of actions focusing on train size, aimed at reducing energy costs by €3.2m per year.

In a statement Iarnród Éireann said 35% of DART journeys are made during off-peak hours. The company is to increase the use of two-carriage DARTs from mid-morning to mid-afternoon, and after 7pm.

The company said the move would, “eliminate unnecessary energy usage and reduce maintenance costs, while continuing existing service frequency to customers.”

Iarnród Éireann is also announcing plans to reconfigure the number of carriages on its Intercity railcar fleet.

"The fleet will be reconfigured to form 45 four-carriage trains and 18 three-carriage trains, allowing greater flexibility in train size as a result by combining train sets together."

Iarnród Éireann said that compared to 2007, energy consumption fell by over one-third last year, with energy bills €16m.