Fine Gael's transport spokesman, Mr Denis Naughten TD, has accused the Minister for Transport, Mr Brennan, of "turning a blind eye to his own policy" by allowing Iarnród Éireann to "wind down" rail freight.
He said the Minister "must come clean about his real plans for rail freight because Iarnród Éireann is pressing ahead with its programme of rationalisation for its rail freight business - in direct conflict with Mr Brennan's own stated objectives".
Speaking in the Dáil on October 7th, the Minister said: "I fully support the use of our railways for beet and other freight transport" and added that he was "a strong supporter of freight on the lines."
But Mr Naughten said the evidence was otherwise.
"It was recently announced that Iarnród Éireann's Sligo and Mallow depots will both close," he said. "Guinness traffic to Sligo will now be delivered to Longford, which is 55 miles away, while container traffic will go to Ballina, which is 37 miles away." Freight traffic would continue its journey by road "while the Sligo line, in which millions of euro has been invested in recent years, would lie idle".
A large gantry container crane installed in the Sligo yard with EU aid was to be removed and sold off.
"The doomed Mallow yard handles freight for the Nestlé company as well as beet trains. Nestlé currently runs a daily train to and from Mallow. The closure of this service will result in more heavy goods vehicles using our already-congested roads."
Mr Naughten said traffic congestion and road accidents would "increase dramatically" if Iarnród Éireann was allowed to press ahead with winding down its rail freight business, and he called on Mr Brennan to act on the issue "or shut up".
Mr Mark Healy, joint editor of the online Irish Railway News, said he was also concerned that "this programme of closure by stealth" would leave remaining rail freight customers "so frustrated with the service level that they will be forced to shift to road transport".
He added: "It seems clear that Iarnród Éireann have no long term ambitions in the rail freight area. The cement business is being operated with life-expired wagons and it would appear that there are no plans for their replacement. Similarly with the beet traffic."
A spokeswoman for Iarnród Éireann denied that it was "winding down" rail freight. She said only container freight was being discontinued in Sligo - the oil and timber business would continue there "and even expand as a result a new deal with Coillte".