MAKOHINE VIADUCT

Wanganui Chronicle, Volume 76, Issue 107, 9 May 1933, Page 4

MAKOHINE VIADUCT

INTERESTING RECONSTRUCTION [ Special to “Chronicle.”] OHINGAITI, May 8. Travellers on the Main Trunk rail way line who, during the past twelve months, have wondered, why the trains have slowed down to six miles per hour when crossing the 750-feet long Afakoliine Viaduct which spans the gorge 242 feet above the Alakohiue Stream, may have appreciated the opportunity to enjoy more than a fleeting glimpse of the beautiful scenery to be viewed from that vantage point, but very few have had any idea of the interesting work proceeding under the decking of the viaduct. Increased weight in rolling-stock and the hauling of greater loads, made X’.ossible by the addition of new and up-to-date engines, has necessitated the strengthening by the Railway Depart ru ent of this viaduct. The reconstruction work was commenced about fit teen months ago when, two miles south of Olungaiti, a siding was run in to the lip of the gorge and workshops were erected and accommodation provide 1 for the men to be employed on the work. Three months were spent in preparatory work and the actual strengthening work, on which sixteen men have been employed, has taken nearly twelve months, the welding of the last bay being completed on the afternoon of Al ay 4. Tho viaduct consists of two 40-fect approaches, two end spans each 247 feet long and one centre span 176 feet long. These three spans are divided into bays, of which the centre span contains eight, and the two end spans ten each ; a total of twenty-eight bays. It is the increasing of the number of these Lays that has comprised the main reconstruction work, one new bay being fitted between each two of the existing bays. Each new bay, consisting of two verticlcs and one floor beam, together with the necessary bracings and fittings, has been fabricated in the workshop where two of the six welders are employed, and the assembled member has then been incorporated into the structure. Four welders. working underneath the rails and decking on a* narrow trackway—seemingly so insecurely perched 240 feet above the stream—received the masrive sections which were swung into position by a crane and which fitted with mathematical precision into the existing framework. These sections were then welded into the structure, and not the least interesting feature of this reconstruction work is the fact that for the first time in New Zealand electric arc welding has been used in place of riveting. Tho oxy-acetone plant has boon in use also in the workshop whore by this moans, great shoots of half-inch stool were cut ns easily as if they had been of cheese. Altogether over one hundred tons of steel has boon welded into the structure, which has now boon strengthened to meet estimated requirements for many years. Tho reconstruction work is. however, iel vet complete. The viaduct has now to be ro-slocporod and TO-deckod. and this work, together with other small jobs, is expected to take another twelve months to complete. Tho painting of the structure has also to be undertaken before the reconstruction work can bo <?aid to be complete.