New Zealand Government Railways 4-8-2 Locomotives in New_Zealand

Class J/Ja (Locobase 2486)

Some of the first 40 engines (all from North British and shipped 12,000 miles by sea after World War II had begun) were delivered with streamlining, a cosmetic adornment only given that these engines ran on 53-56-lb rail and were normally limited to 55 mph. The Westconn Manifest, published by Western Connecticut chapter of the NRHS, says in its January 2005 issue ([] , accessed 22 January 2007), that the JA's streamlining was based on the New Haven's I-5 4-6-4s.

They had 4" bar frames, high-tensile-strength steel alloy main and side rods to reduce weight. Tonnage ratings were 400-ton passenger trains or 800-ton freight trains (OS Nock (RWC VI, pl 107) says 1,000 tons for freights.).

Ja engines (35 built at Hillside) were the principal engines on South Island; they had roller bearings that produced, says The "Steam Incas" website ([]), "...a very friction-free and quiet-running engine requiring the minimum of greasing and preparation time" Jb (16 by North British) were oil-fired and used near Auckland on the North Island. These engines occasionally reached 70 mph.

The Steam Incas say further: "...they were to prove to be a very free-running and generally trouble-free locomotive capable of further refinement in later years. They were intended to provide more powerful locomotives for use on those routes laid with lighter track that would not carry the much heavier Ka." In describing the popularity of the surviving J1234 with railfans, the website notes: "Like most of the J and Ja classes it ...has that typical ability to whip a train into frantic activity when accelerating away from a stop."

Class X (Locobase 5195)

Data from John Garner's comprehensive site at [] ... (October 2002), supplemented by diagrams supplied by NZGR's general manager T Ronayne in "Locomotive Building in New Zealand", Railway Engineer, Volume 34, No 6 (June 1913), pp. 183-186.

These large de Glehn compounds were designed by the NZGR's CME A L Beattie to provide passenger power in the North Island's central region, an area of tough grades. Built at the Addison shops, these might have been the very first "Mountains" built anywhere, Garner suggests. Eleven were rebuilt in 1951 as four-cylinder simple superheated engines; see Locobase 5196.

[] (16 May 2003) has a long post from Derek Brown dated Wed Jan 3, 2001 6:51 pm on this design:

"...They were a hybrid De Glehn with divided drive & Walschaerts's [sic] valve gear. They had two reversing levers, one for the inside HP valve gear, the other for the outside LP valve gear. Brown says they were "... a low speed machine (30 mph max), but had heaps of power. The Firemen hated them because the front section of grate area sloped down between the 3rd & 4th axles, & this section had to be kept clear of green fuel or else steaming would become inhibited."

One of RE's diagrams clearly shows the de Glehn layout from overhead. The two HP cylinders lay between the frames and under the smokebox. They had very short rods driving on the lead axle. Outside of the frames, behind, and just clear of overlapping the HP cylinders were the two LP cylinders, which turned the second set of drivers. Loading gauge limitations may have led A L Beattie to adopt unusually square cylinder diameter/cylinder stroke dimensions.

Class X - rebuilt (Locobase 5196)

Data from John Garner's comprehensive site at [] ... (October 2002). These were the rebuilt X-class Mountains designed by AM Beattie for use on the mountainous section of the North Island main line. Ten were made over at Hutt and one at Hillside. Simpling the 4 cylinders was one thing, but the rebuild also seems to have reduced the boiler dimensions considerably if Garner's figures are correct.

During the 1940's on, these locos were converted to four- cylinder simple machines, using the original cylinder castings with the LP cylinders sleeved down in diameter; boilers were superheated; some boilers were fitted with two Nicholson thermic syphons. Air operated power reverse was also fitted."

[] (16 May 2003) has a long post from Derek Brown dated Wed Jan 3, 2001 6:51 pm on this design. After discussing the compound X (see Locobase 5195), Brown continues: "I knew this class of loco intimately, they rode well, pulled well, & Fireman (I was one), still hated them, probably even more than when they were compounds. They were a mobile work house because the bunker was not of the self trimming type, therefore the poor old Fireman spent a lot of time heaving coal from the back of the bunker to the front, & from the front into the firebox. It was a rare occasion to pass a water tank without stopping, their appetite for water was out of this world."

After his extended dissection of the design's shortcomings, however, Brown concludes: "To sum up, it is believed that in spite of their faults these locos were a success - they did what they were designed to do - to haul heavy trains over our mountainous central section."