Railway Bridges

The Dargan Bridge

Rapid progress was reported on the railway works to Carlow. By late June 1846, nearly all the cuttings were completed to within a few yards of the terminus. The "Carlow Sentinel" of June 27th reported that the bridge crossing the Dublin Road "is a singular work of art". At the time of its construction it was perhaps the largest skew-bridge in the world.

Dargan Bridge

The Dargan Bridge designed by William Dargan and completed in 1846.

Carlow County Library

Dargan Bridge
Carlow County Library

Dargan Bridge

The Dargan Bridge designed by William Dargan and completed in 1846.

Carlow County Library

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The plan of the structure was devised to overcome the difficulty of the construction of bridges to suit the curvature of the railways. The abutments to two of the opposite acute angles measured 43 degrees and were consequently 47 degrees in deviation from the right angle or square. The formation of this "singularly oblique" arch commenced at these opposite angles and continued on in spiral courses until they met. The last spiral courses formed the key stones of the entire arch. Work was completed on the bridge by circa July 11th 1846. The "Carlow Sentinel" of that date called it "the finest specimen of an oblique bridge" in the kingdom.

The contractors for the work were Mr. Daniel Brown and Sons under the direction of William Dargan. It was built in three weeks by men who had no experience of similar work. The stone-cutters had sought increased wages. William Dargan refused to accede to them. He dispensed with their services and employed labourers instead. They finished the work within the specified time.

Viaduct over the Barrow

On April 12th 1847 Philip Newton of Dunleckeney House, performed the ceremony of laying the first stone on the viaduct over the Barrow near Bagenalstown. A great number of the gentry and local inhabitants were present. Among the attendance were John Alexander of Milford who was a director of the railway, Doctor Roche of Bagenalstown, Joseph and Matthew Weld, the Lodge, J.W. Nicholls, Resident Engineer and Mr. Brown. The gentlemen proceeded to the location for the work and the mortar was spread by the foreman mason. Mr. Newton placed the stone in its proper position and "struck it three blows with a mallet in true workmanlike manner". Those in attendance gave three hearty cheers for the directors of the railway and three more for Mr. Newton. Toasts were raised to the success of the undertaking.

The viaduct was designed by Sir John Macneill, engineer-in-chief and consisting of five arches over the River Barrow and two additional land arches. All the arches are semi-circular and of the same span namely, thirty feet. The viaduct is of limestone "of a very superior description". This stone was available in the neighbourhood and it was expected to take 16,000 tons of stone to complete the viaduct.
At the time of opening Mr. Dargan the eminent contractor hoped to have it finished by October 1847. he also planned that since this was the only work of magnitude on the line, that therefore it was probable that the railway line from Carlow to Kilkenny would be opened by the end of 1847.