GOING ON WELL

Dominion, Volume 23, Issue 169, 12 April 1930, Page 15

GOING ON WELL

TAWA FLAT TUNNELS PROGRESS OF WORK INSPECTION BY MINISTER Good progress is being made with work on the Tawa Flat railway tunnels, according to a statement made by the Minister of Public Works (Hon. E. A. Ransom) yesterday following an inspection of the undertaking. “The total length of No. 1 tunnel,’’ said the Minister, “is 05 chains, and the width is 24ft. From the southern portal, Hutt Road, the tunnel has been enlarged and concreted for a distance of 18 chains, also for a distance of 15 chains from the northern portal,” Ngahauranga Gorge. There are now 26 chains of enlarging and concreting to complete, the centre heading for that length having been driven some time ago. At the present rate of progress it is estimated that No. 1 tunnel will be completed in about 12 months’ time.” The Minister mentioned that the small battery locomotives used for bringing the earth-laden trucks from the centre heading to the south portal had been supplemented by a locomotive which obtained Its power from overhead wires, similar to those in use in No, 2 tunnel, and which was placed into commission on Wednesday last. Whereas the small locomotives pulled three to four trucks, each of which held ’two cubic yards of material, the locomotive hauled eight or nine. No. 2 Tunnel. Referring to No. 2 tunnel, which is 2 miles 53 chains in length, the Minister stated that from both ends distances of ten chains had been enlarged and concreted. Satisfactory results were being obtained from the use of the big steel profile in the concreting work. The walls were first battened and then the profile, which was 24ft. wide and 20ft high, was jacked on a gantry and placed into position. From the compressed air guns the concrete was fired into the space between the profile and the walls, and when the mixture was set the jacks holding the profile were released and the profile moved along by the gantry to a further section ahead. “This is an advantage on the old system,” said the Minister, “and it saves the man-handling of heavy wooden moulds, and at the same time gives a better finish to the work. For the holding of the country before the concrete is placed, lOln. by .lOln. New Zealand timber is being used throughout.” Cutting Down the Time. The Minister mentioned that an interesting feature of the method of attack in the second tunnel was the driving of a pioneer tunnel, 10ft. wide and Bft. high, running parallel to and ahead of the main tunnel and 66ft. away from it. At various points along the route little “side streets” bad been cut into the course the main tunnel would follow. enabling the main objective to be attacked at as many points as was desired, besides the two ends. This method would, it was intimated, save at least a year in the completion of the big tunnel. The Minister added that he had taken advantage of the opportunity to investigate the complaints placed before him recently by the men, and to examine conditions on the spot.