Irish Rail has described lorry drivers who ignore height restrictions at bridges, as "dumb truckers".

The rail company says the basic intelligence of truck drivers has to be called into question over the increasing number of bridge strikes.

Irish Rail says it has worked to inform lorry drivers through improved signs and new technologies.

The company says large vehicles hitting bridges is one of the greatest safety risks that Iarnród Éireann faces.

Spokesperson Jane Cregan, says the high number of bridge strikes calls the competency levels of truck drivers into question.

"It's a fairly basic thing to know the height of your vehicle before you transport it through a restricted bridge height area," she said.

"The basic intelligence and competence of drivers involved in these incidents must now be called into question.

"Last Thursday, we had two bridges in the Grand Canal Dock area struck by two different truckers within two hours of each other causing massive delays in services and massive traffic disruption."

Iarnród Éireann must carry out a structural assessment of the bridge before allowing trains to pass over following a hit,

In a statement, Irish Rail said that in 2014, there were 85 bridge strikes across the network, but this year to date alone there has been 68 bridge strikes. DART has seen the largest increase in the number of collisions with 25 taking place this year already, compared tpo 12 in the same period last year.

The company added that hitting of bridges by large vehicles is one of the greatest safety risks it faces.