610 PROCEEDINGS OP SECTION J. 



are seven viaducts, all built of masonry set in Portland cement. 

 These viaducts are of an aggregate length of two thousand two 

 two hundred and twenty-five feet, varying in height from ten feet 

 to seventy feet, and in spans from ten feet to fifty-four feet. There 

 are also three tunnels, one on the Lithgow Y alley Zigzag, seventy- 

 seven yards in length, one at Morangaroo, two hundred and sixty- 

 seven yards in length, and one under tlie Mudgee-road forty-seven 

 yards in length. Beyond Wallerawang the line passes through 

 Rydal and down the valley of the Solitary Creek, over which stream 

 seventeen plate web girder bridges have been erected in a distance 

 of nine miles ; they consist of thirty feet, fifty feet, sixty feet, and 

 sixty-six feet spans, and the abutments and piers are of brick, set 

 in Portland cement. 



The bridge over the River Macquarie at Bathurst, one 

 hundred and forty-four miles from Sydney, is constructed for 

 a single line of railway, with two continuous wrought-iron 

 lattice girders, four hundred and eighty feet each in total 

 length, twelve feet six inches deep, and placed fourteen feet apart. 

 It is divided into three spans of one hundred and fifty feet, each 

 span being supported on two cast-iron cylinders nine feet in 

 diameter, sunk to a solid foundation of an average depth of 

 fourteen feet below the ordinary level of the water in the river. 

 Ihe cylinders are filled with concrete, composed of gravel and 

 cement in the proportion of six to one. The details of this 

 bridge are similar to those of the Wagga Wagga iron bridge. 

 The maximum deflections observed with a live load equivalent to 

 1-4 tons per foot run were '82 inches in the side spans, and -75 

 inches in the middle spans. 



The bridge over the River Macquarie at Wellington is 

 similar in design to the Bathurst Bridge ; there is, how- 

 ever, an approach span on each side, consisting of two main 

 plate web giixlers, sixty-one feet span in the clear, and six 

 feet deep, with a deck similar to that on the main bridge. The 

 maximum deflections obtained with a live load equivalent to 1 -4 

 per foot run on the main spans were -92 inches on side spans, 

 and "52 inches on the middle spans. The maximum deflections 

 observed on the approach span with a live load of 1 -5 ton per foot 

 run was "36 inches. 



The bridge over the River Macquarie at Dubbo is similar 

 in general design to the bridges at Bathurst and Wellington. 

 It consists of three main openings of one hundred and fifty 

 feet in the clear, and two of sixty feet, one on each side of 

 the main openings. The two main lattice girders are each con- 

 tinuous over two piers ; they are four hundred and seventy-seven 

 feet long over all, and fifteen feet deep. There are four systems 

 of triangulation, and the details of the main girders are similar 

 to those of the Albury Bridge. The piers consist of cast and 



