s. Steam to Southland

10th August 2007

The railway from Christchurch to Dunedin and Invercargill traversed the provinces of Canterbury, Otago and Southland and was the proving ground of some great locomotives. Constrained by the very narrow firebox dictated by the 3’6” track gauge, the ten wheelers assigned to the Dunedin express could not develop enough horse power to improve the train schedule, especially burning poor grade Canterbury coal. The NZR’s Chief Mechanical Engineer from 1900 was A.L.Beattie, one of the great colonial engineers. Beattie needed a super ten wheeler, and conceived the notion of adding a trailing truck to support the big Wootten firebox and ashpan needed for burning low calorific coal. In 1901 he contracted the Baldwin Locomotive Works to build ten of these locomotives, and the long voyage across the Pacific gave the new 4-6-2 wheel arrangement its name.

The new Q class was assigned the Dunedin Express, but Beattie wasn’t satisfied. As remote from Paris or London as it is possible to get, and before the aeroplane and radio, he was aware of Churchward’s experiments with De Glenn compounds on the Great Western Railway, and set about perfecting his Pacific. Outshopped from the NZR’s own Addington (Christchurch) Workshops in 1906, the four cylinder compound A class was a stunning locomotive, and further accelerated schedules on the South Island Main Trunk. That was good, so Beattie then applied the same logic to the 4-8-0, and two years later Addington produced the world’s first 4-8-2 “Mountain” type, also a four cylinder De Glenn compound. But more was to come. Beattie had one of the A class Pacifics built as a two cylinder simple expansion engine, just to compare performance against the compounds, as Churchward had done. In 1909 this engine was fitted with one of the newfangled superheated boilers, only three years after the Churchward’s first experiments with Schmidt’s patent. The results were outstanding, and the next class of Pacifics was built to this arrangement. The Ab class of 1915 was claimed to be the first locomotive to produce one horse power for every 100lbs weight. Finished under the supervision of Chief Draftsman S.H. Jenkinson after Beattie’s retirement, it became the defining NZR locomotive, and held down the top job on the Invercargill Express for a generation. One can only wonder what the design offices in Australia thought about these developments, and what transpired at the ANZR Conferences! It was another two years before the NSWGR built an engine with a superheater, and some Australian systems waited until the 1920’s to adopt it. The narrow gauge systems, with the exception of the Tasmania, remained doggedly committed to the 4-8-0, and resisted the Pacific until the mid 1920’s.

The Invercargill Express was upgraded in 1939 with new carriages a new bullet nosed 4-8-2’s. The rakish J class was a magnificent machine, and put up some impressive performances over the Canterbury Plains, with sprints over 70 mph when making up time. As more of these light Mountains were added after the War, the Ab was relegated to goods and branch line service, many remaining in service for over 50 years.

The NZR initially devoted its dieselisation efforts to the more populous North Island, and by late 1967 the only diesels in the South Island were those on the Kaikoura Coast line north of Christchurch, and some shunters. Steam ruled elsewhere. There were 4-8-4’s in the Midlands, Mountains on the Plains, Pacifics in the hills and Tanks in the yards. After experiencing all the Australian 3’6” gauge systems (except Tasmania), I was amazed at the speeds attained in New Zealand and the quality of their track. The locomotives were wonderful, the crews friendly and the scenery stunning. My visit in December 1967 was just in time. This is the end of an era on the South Island Main Trunk and its branches!

Beattie’s Best	Did Anyone Notice?	Wee Suburban at Dunedin	Younger Than Bert’s Indian
Interesting Connections	Submarine Railway	Win Win	Trans Tasman Tank
Main Line Electric	South Island Limited	Light Footed	Weight Saving
Overdue	The Longest	Engine Requirements	Tight Fit
NZR Classic