HAY, Peter Seton, (1852 - 1907),
HAY, Peter Seton (1852 - 1907), was born in Glasgow and came with his parents to New Zealand in 1860. He was educated in Dunedin, becoming the first B.A. of Otago University in 1877, following this with the degree of Master of Arts next year with first-class honours in mathematics. This was the more meritorious as he had joined the Public Works Department as an engineering cadet on 13th June, 1875, being stationed for a short time in Wellington. No doubt to assist his scholastic aspirations he was transferred back to Dunedin on 6th May, 1875, being engaged, amongst other duties, on the survey and construction of the Dunedin to Moeraki and the Dunedin to Clinton Railways. At the end of his cadetship he was in 1879 promoted to Assistant Engineer at Dunedin. Though nominally at Dunedin, his work included the survey of the Otago Central Railway from Rough Ridge to Hawea. He was at Cromwell in 1881. It was during this work that it is recorded that he left his book of logarithms and trigonometrical tables (Chambers) in camp, and rather than waste a day or walk back for the book he sat down behind a rock and proceeded to work out the necessary tangents, etc., from first principles. He also surveyed the railway from Balclutha to Catlins River. On 1st May, 1884, his brilliant mathematical talents having marked him out as a head office man, he was transferred to Wellington, being two years later graded as Resident Engineer. His duties, however, were chiefly design work and assisting the Engineer in Chief on difficult problems. In 1894 with E. R. Ussher, q.v., he reported on the enormous accretion of sand taking place in Caroline Bay. He recorded that the three fathoms line had moved 700 feet seaward since the construction of the harbour works. In 1896 he was promoted to Superintending Engineer [now called Assistant Engineer in Chief] .In 1899 he was associated with T. H. Rawson as a commission to report on the proposal of J. P. Maxwell to construct a new East mole at Timaru. On 29th January, 1906, he became Acting Engineer in Chief and was confirmed in that position on 1st April, 1906, on the retirement of ,W. H. Hales. He also became Marine Engineer. He designed the Makohine, Mangaweka, Hapuawhenua, Toanui, Manganui-o-te-Ao and Makatote viaducts, and many other bridges on the North Island Main Trunk Railway, the Awatere two-decker road and railway bridge; the Farewell Spit Steel Lighthouse, and many other big works. He advised on the restoration of the Rakaia Gorge Bridge wrecked by wind, and the strengthening of the Christchurch Exhibition towers. Also on Motueka Harbour. But he will always be remembered for his exhaustive 1903 report on the hydro-electric potentialities of New Zealand.
Probably his greatest work was the solution of the problem as to the best way for the railway to cross the Southern Alps. Many schemes had been tried, and at the stage when Hay came into the question the Midland Railway, after trying and rejecting a 1 in 50 series of grades over the top, and other ideas, had finally pegged out a location for grades of 1 in 15 on each side of the range with no summit tunnel He came to the conclusion that the best grade that the country would allow on each side, following the valley bottoms without undue earthworks, should be adopted, and then the open-air work should be connected by a tunnel on the grade which was then required, approximately 1 in 37. The tunnel was to be about 6¼ miles long. The Government of the day, on the principle that distant fields look green, decided to bring from North America a railway engineer of outstanding reputation and ability, Virgil Gay Bogue, and to obtain from him a report on the whole problem. He considered that a certain amount of grading up and development on the western side on a grade of 1 in 30 should be done and that the tunnel, on a grade of 1 in 33, could then be reduced to about 3½ miles. Hay prepared a counter report and proved that if 1 in 30 grade, which Bogue had recommended, was not too steep, then an almost straight line could be built (without the development in rough country, with attendant slip and avalanche dangers), which would be shorter than Bogue's line, no steeper, and would cost less, even though the tunnel would be over 5¼ miles long. Hay's grade throughout was 1 in 33. When this new solution was referred to Bogue, he was fair enough to admit that Hay's solution was the one which should be adopted, and it was. This the writer considers Hay's greatest triumph, but unfortunately he did not live to see its consummation. He died on 19th March, 1907, as the result of illness brought on by exposure when inspecting the works on the North Island Main Trunk Railway.
Extract from Furkert’s "Early New Zealand Engineers" pp 183-5
Lowe, Peter. 'Hay, Peter Seton 1852/1853? - 1907'. Dictionary of New Zealand Biography, Volume 2 - 1870 - 1900