Melton viaduct is situated near Melton South in Victoria around 45km west of Melbourne CBD, over the Werribee river. The viaduct was completed in 1886, by Victorian Railways as part of the Melton – Parwan section of the railway line, which established direct rail route between Melbourne and Ballarat. Melton Reservoir was constructed here in 1916 to supply water for irrigation around Werribee. The viaduct, 375 metres in length and 40 metre above the Melton Reservoir was listed on the Victorian Heritage Register in 2013. The structure is constructed entirely of wrought iron. The first through express train from Adelaide to Melbourne passed through the viaduct in 1887.
The iron work for the bridge was brought from England manufactured by Handyside and Co and the total cost for the bridge was around £120,000, when completed. John Robb was the contractor for the viaduct and around 200 men were employed for the work. The engineers in addition to providing for the rush of flood waters had to take into consideration the extreme pressure of high winds, which was in some instances so severe that men engaged in erecting the deck work had to cease their labours for fear that they would be blown off the structure (The Argus, 16th March 1886)
The iron work imported from England were erected by Mr. Mastell without a single accident. Mr. J H. Thomson supervised the iron work, and Mr. W. C Bellings did the masonry and foundations on behalf of the Railway department. Mr. J. Buchanan was engineer; and Mr. T. Stranger, the manager for Mr. John Robb, the contractor (The Illustrated Australian News, 31st March 1886).
The type of construction differed from the way Victorian Railways constructed Railway bridges in the 1860’s. The absence of heavy stone piers were compensated by the strength of erection. The prefabricated components were assembled with travelling cranes using the incremental construction technique which was considered revolutionary on those days. This was the second longest metal truss bridge in Australia after Moorabool railway viaduct in the 1860s.
The Age on 29th May 1886 published this information about Melton Viaduct
The work of constructing the Bacchus Marsh line from the junction at Braybrook to the southern edge of the vast amphitheatre which almost encircles the township of Bacchus Marsh was commenced early last year by the contractor, Mr Robb. The greatest difficulty encountered was in the erection of the colossal iron viaduct over the Werribee River, about two miles and a half beyond Melton. As the super incumbent weight of iron would be something like 1400 tons it was necessary, in the first place, to obtain a solid foundation on the bed rock. For several months, the officers of the Railway department were engaged in boring with this object.
Owing to the immense amount of drift earned down the river by floods, and the fact that the bed rock had been disturbed by volcanic action, evidence of which may be seen on all sides, considerable difficulty was experienced before a solid foundation was found. The viaduct crosses the Werribee at a point where the river is divided into two channels by means of a largo central bank, on which rest four of the supporting trestles. The structure, which is known as an iron trestle viaduct, was designed by Mr. T. T. Thomson, of the engineers’ branch of the Victorian railways, and is the largest and most striking of its kind in Australia. The plans and specifications were sent to England in 1884, and the work of constructing the iron work placed in the hands of Andrew Handyside and Co. of Derby, early in the same year. The bridge was imported in sections by the builders and erected by them upon the foundations laid down by Mr. Robb, the contractor for the line. It consists of 29 trestles, which rest upon bluestone foundations filled with concrete covering. The total length is 1260feet. The height of the top rail above the bottom of the river is 126 feet. The height from the stone tower on which the trestles rest to the rails is 88 feet, and as the sides of the trestles have a batter or inclination of 1 in 8 they present a graceful appearance.
At the same time, they are well stayed, and whilst presenting the smallest possible surface area to the wind, secure a maximum of strength both laterally and longitudinally. To give some idea of the weight of the columns it is necessary to state that the total dead weight at the outside of the highest column is 27 tons, and 48 tons at the centre column, whilst the exact weight of the whole viaduct as it stands at the present moment is 1430 tons. It is calculated that with two trains on it, and a hurricane of wind traveling at right angles at the rate of 79 miles per hour, which would be a pressure of 30 lb. per square foot, the compression would be 2.9 tons per square inch at the bottom of the outside column.
A short time ago the viaduct was practically tested in the presence of the Railway Commissioners and the officers of the Railway department. Four locomotives (two tank and two heavy tender engines), weighing altogether 190 tons, were run on to the viaduct, the maximum depression of the centre column of which was only l-64th of an inch. The locomotives wero then sent across at the rate of 40 miles an hour singly. Steam was shut off and breaks applied at the commencement of the viaduct, and also in the centre for the purpose of showing the lateral vibration. As observed by the theodolites this never exceeded one-eighth of an inch.
The tests were considered highly satisfactory, and fully realised the expectations of the engineers. On the Melbourne side of the Werribee the viaduct is approached down a falling grade and on a curve. Although the driver may not be able to look straight ahead and across the bridge to see if all is right, he has a pretty fair side view of the structure.
Although there is not the slightest danger to be apprehended, there is no doubt an engine driver descending the bank with a heavy goods train behind him would prefer an easier gradient. It would give him a better opportunity of keeping his train under control when running on to the viaduct. The view from the latter whilst crossing in a train is a remarkable one, and well worth a visit.’’
Address: Over Melton Reservoir Brookfield and Hickey Road, MELTON SOUTH VIC 3338