The trials will see the maximum length of freight trains increase from 18 wagons with 36 TEUs to 27 wagons carrying 54 TEUs. As well as increasing the capacity and competitiveness of rail freight services, IE says the environmental benefits of rail freight will also be enhanced. "Currently moving freight by rail instead of road reduces emissions by up to 75% per unit, and longer trains could see emissions reduced to as little as one-tenth of the road equivalent," IE says.

Trials undertaken in recent weeks include a 440m-long 27-wagon container train weighing 1110 tonnes, a 390m 18-wagon pulpwood train also weighing 1100 tonnes, and a 1310-tonne weight test using ballast-laden wagons.

IE freight traffic reached 96.4 million tonne-km in 2015, and the main rail freight flows currently include container traffic from Ballina to Waterford and Dublin ports, pulpwood from Ballina and Westport to Waterford port, and zinc ore from Tara Mines in Navan to Dublin port.

Subject to the successful conclusion of trials, IE plans to start operating longer freight trains in the fourth quarter of 2016.