Percy Roy Angus was born in Wellington on 22 September 1893, the son of Matthew Angus, a railway clerk, and his wife, Ann Jane Bell, who were both originally from Auckland. He was educated at Greymouth District High School and Southland Boys’ High School (1908–10), and at Canterbury College. He later became an associate member of the Institution of Mechanical Engineers, London.
From 1910 to 1915 Angus was a mechanical engineering cadet with the New Zealand Railways, initially at Invercargill, then at Addington and finally Wellington, where he was a draughtsman in the chief mechanical engineer’s office. From September 1916 to October 1918 he served in France with the New Zealand Expeditionary Force as a lieutenant in No 3 Field Company, Corps of New Zealand Engineers. After his return in 1919 he became an assistant locomotive engineer at Auckland, and two years later he was promoted to locomotive engineer, based at Greymouth.
A tall, slim man with fair hair and blue eyes, Percy Angus married Scottish-born Ann McKenzie on 8 November 1923 at St Andrew’s Church, Wellington; they were to have two sons and a daughter. He was transferred to the chief mechanical engineer’s office in Wellington the following year, and soon afterwards embarked on a 12-month study tour of Australia, South Africa, Europe and North America. On his return in 1926 he was briefly locomotive engineer in Christchurch, before returning to Wellington as assistant chief mechanical engineer. He was to live in Wellington for the rest of his life, initially in Wadestown, then from the early 1940s in Lower Hutt.
Although the New Zealand-designed 4-6-2 Ab-class locomotive had proven successful, with over 140 built between 1915 and 1926, Angus found while in South Africa that the standard goods engine there, operating on the same narrow-gauge track, was twice as powerful. By 1925, due to the rapid increase in the volume of railway traffic, it was apparent that excessive double-heading of trains over the steeper grades in the central North Island would become necessary, causing unproductive mileage and increased running costs. The New Zealand Railways needed more powerful locomotives, but a trial of three Garratt engines imported in 1928 proved disastrous: they were too powerful for the existing rolling-stock drawbars and breakages were common; engine maintenance was also a continuing problem. In 1929–30 Angus spent another year overseas – in Canada, the United States, England, Scandinavia, Germany, Switzerland, Austria and Argentina – studying diesel haulage, but he returned convinced that it was not yet the answer for New Zealand.
Therefore, in July 1930 he obtained approval to design a steam locomotive with a tractive effort of about 30,000 pounds (50 per cent greater than the Ab) but which met all of New Zealand’s loading-gauge and weight requirements, and could be readily and economically built and maintained locally. Working within limits far more stringent than most other railways, Angus (who became locomotive superintendent in December 1931) and his chief designer, R. J. Gard, devised the K-class locomotive. Between 1932 and 1936, 30 of these 136-ton 4-8-4 locomotives were built. Described by the American writer S. Kip Farrington as ‘easily the best-designed locomotive operating on [three-foot six-inch] gauge to be found anywhere’, the K class attracted international attention and was to serve New Zealand for three decades.
Yet Angus felt that the K class and other rolling stock could be further improved. He had noted that the Swedish national railways had adopted roller bearings for all railway stock and arranged for them to be fitted on some new carriages. The normal journal bearings used on main-trunk carriages had to be renewed about every three months owing to excessive wear, but roller bearings overcame this problem, as well as the problem of hot bearings. Passengers no longer had to vacate sleeping cars at inconvenient times and places and scramble into already crowded day cars. Eventually many carriages, some special wagons and 41 new Ka and Kb locomotives were equipped with roller bearings, greatly increasing their mileage (particularly for locomotives) between major maintenance overhauls.
Because the K-class locomotives were too heavy for some secondary lines, the J-class 4-8-2 type was developed. Designed in New Zealand, 91 of these locomotives were built here or in the United Kingdom from 1939, and they too proved to be an outstanding success. Another of Angus’s achievements was the successful introduction in the 1930s of new railcars on the Wairarapa and New Plymouth lines. In 1941 he became chief mechanical engineer for the New Zealand Railways, with full control over workshops and all locomotive running.
When the decision was made in 1946 to undertake the electrification of the Hutt Valley lines, Angus and chief accountant F. W. Aickin went to the United Kingdom to complete the purchase of the new rolling stock. In 1949, with the era of steam drawing to a close, he was part of a New Zealand Railways technical mission that visited Canada, the United States and Europe to decide what system of mainline electrification was best for New Zealand. Angus retired in 1950 but maintained his railway association as a manufacturer’s representative. In 1951 he was appointed an ISO, and in 1952–53 he served as president of the New Zealand Institution of Engineers. He died at his Lower Hutt home on 7 July 1961, survived by his wife and children.
A mechanical engineer who was quick to note overseas practices of benefit to New Zealand, Percy Angus was also a capable and popular administrator who was able to ensure their successful implementation. He was responsible for a series of major advances which made the service provided by New Zealand Railways the equal of any in the world. He is commemorated by the annual Angus award of the Institution of Professional Engineers New Zealand for the best mechanical engineering paper.