TESTING THE MAKOHINE VIADUCT.

Lyttelton Times, Volume CVIII, Issue 12933, 29 September 1902, Page 3

TESTING THE MAKOHINE VIADUCT.

AN INTERESTING PROCEEDING. ; The “ Huntervill© Express ” reports that the official testing of the Makohine Viaduct took place last Sunday. The first day of the week was for the obvious reason that the railway engines required for the work could not be spared at any other time. The test was made under the most unfavourable of meteorological conditions, there being a strong breeze, which at times increased to a gale, accompanied by srain. The conditions pointed to the viaduct being subjected to a lateral pressure by nature as well as by a downward pressure -by the engines of man. Some people were inclined to think that under the circumstances the test would bo postponed till the elements were more, propitious, but this idea was dispelled when a “live’.' railway engine, with six “dead” ones behind and a carriage containing officers of the Department and a number of visitors arrived from Wanganui. The “ live ” engine had so heavy a loa.d that it .seemed not to have enough wind left -to give forth a decent whistle. The procession consisted of six locomotives, weighing about thirty tons each. Amongst tho officials present were:—Mr Hay, designer of the viaduct• Mr MTritosh, District Engineer for Working Railways; Mr Cruch, Inspector of Permanent Way; Mr Cook, Resident Engineer; and Mr Eraser, Inspector of the Public Works Department. Mr Sneddon, who superintended tb© manufacture of the ironwork and erection of the structure, was also present. The company of onlookers included half a dozen photographers. The method of testing was as follows: First, two engines ran -across the viaduct and returned ; next all the eight engines, with trucks loaded with ballast between each, proceeded slowly over, the whole weight amounting to fully 600 tons. The trucks and two small, engines‘were left on the Ohingaiti side; and the remaining engines kept moving backward and forward on the structure, stopping every fifteen or twenty yards. All the locomotives were coupled together; so it is easy to realise that every part of the bridge was subjected to an enormous pressure. As far as the ordinary observer could see the structure stood as firm as a rock. A gentleman who has given some time to tho study of dynamics and mechanical science generally, informed the “ Express ” representative that from the observations ho was able to make, there was not the slightest deflection, though doubtless the bridge must have, according to the principle of construction, yielded under the great pressure. Never again (says the “Express”) will the viaduct be called upon to bear anything like the weight put upon it on Sunday. In all probability the carriage of timber will constitute the heaviest traffic on tho line. Roughly speaking, it would take 300,000 ft of timber to make up a load equal ■to that of the eight locomotives and trucks of ballast used for the purposes of the test. The above quantity of timber would be equal to the whole output of a sawmill for three months. The six coupled engines were.the severest trial of tho strength of the, structure, owing .to the concentration of weight at on© time upon a single point. The last stage has thus been passed in the construction of a great undertaking, which, has now been handed oyer to the Working Railway Department, and will in a few days he open for goods and passenger traffic.