New Zealand Government Railways Articulated Locomotives in New_Zealand

Class E (Locobase 6356)

Data from Data from John Garner's comprehensive site at [] (visited 19 Nov 2004).

It may have been "Pearson's Dream" (after G A Pearson, Chief Draftsman for the NZR), but it proved to be more of a nightmare (Locobase couldn't resist ...). Designed for the Rimutaka incline, this Vauclain compound had too many unusual features. For one thing, eight cylinders, even if they're ganged together in pairs sharing a valve train, would normally have been considered too many to keep in trim. Second, the circular Vanderbilt firebox was not a worthy alternative to the standard cubic volume. Third, using two throttles, one for each engine set, just added complication.

The front engine set had its cylinders leading the drivers, the rear engine trailed its cylinders behind the drivers. Although thus resembling a Kitson-Meyer arrangement, the locomotive in fact was a Mallet with front set shifting laterally around a pivot at its rearmost point and the rear set fixed to the frame.

Large, deep side tanks flanked the coned boiler that, relative to total cylinder volume, was quite capacious. Indeed, the locomotive could be made to steam quite readily, especially after the brick arch in the firebox was modified. But when the Rimutaka incline was bypassed by new construction, the requirement for a locomotive that could pull 45 loaded cars up a 1 in 15 (6 2/3% !) grade went away. After less fruitful service as a pusher on the Wellington-Johnsville hill, the E was stored in May 1917.

Class E - Double Fairlie (Locobase 5169)

Data from John Garner and his website [] (October 2002), supplemented by "Fairlie Locomotives for New-Zealand [sic]", Scientific American Supplement, No. 5 (29 January 1876), p. 73. See also Charles Rous-Marten, "New Zealand Railways: Their History, Engines and Work", The Railway Magazine (December 1899), pp. 567+.

Supplied by English builders Avonside (6) and Vulcan Foundry (2), these double Fairlie engines were specifically intended for ruling grades of nearly 3% and very tight curves. Ironically, the design demonstrated a tendency toward cracked frames and the flexible connections from the boiler to the cylinders leaked.

OS Nock (RWC II, pl 24) notes that these locomotives were among the very first Fairlies and the first British engines with Walschaerts gear. Unfortunately for the design, however, Nock reports that the Lady Mordaunt and the others of the class were regarded as a "poor engine with any load". This may be attributable as much to the use of peat in the firebox, which the Scientific American report note explains the size of the grate, as to any substantial defect in the design.

Rous-Marten adds a failure of the railroad to work the engines "in accordance with their inventor's directions." He explained that "Mr. Robert Fairlie often impressed upon me the necessity of his double-boiler engines being worked with full loads, failing which, he said, the advantages he claimed for his method would not be obtained." Rous-Marten turns to the boiler and says using Serve tubes, which were larger diameter tubes with internal fins, didn't offer a significant advantage over more common smooth tubes "unless the engine is worked in its full power, when they show marked superiority." Permanent-way engineers weren't happy to have a 30-ton locomotive rolling over their bridges "albeit distributed over eight wheels." And the double bogies leaked steam through the flexible steam pipes.

"And so," read Rous-Marten's final dismissal in 1899, "the Double-Fairlies are rapidly dying out and are going one by one to the scrap heap without a single tear of regret being dropped on their rust."