Editing 4-8-2 (section)

==Overview==
The [[Colony of Natal]] in [[South Africa]] and [[New Zealand]] were innovators of the {{nowrap|4-8-2}} Mountain wheel arrangement. The [[Natal Government Railways]] (NGR) placed in service the first [[tank engine]]s with the 4-8-2 arrangement, and the NGR was also first to modify [[tender (rail)|tender locomotive]]s to use a 4-8-2 wheel arrangement. The [[New Zealand Railways Department]] (NZR) introduced the first tender locomotives designed and built as 4-8-2.

[[File:NGR Class A (4-8-2).jpg|thumb|left|[[South African Class A 4-8-2T|NGR Class D]]]]
In 1888, the Natal Government Railways placed the first five of its eventual one hundred [[South African Class A 4-8-2T|Class D]] {{nowrap|4-8-2}} tank locomotives in service. The locomotive was designed by William Milne, the locomotive superintendent of the NGR from 1877 to 1896, and was built by [[Dübs & Company]]. This was the first known use of the {{nowrap|4-8-2}} wheel arrangement.<ref name="Holland 1">{{Holland-Vol 1|pages=72–75, 90–95, 99–105, 124, 134–135}}</ref>

[[File:SAR Klasse 1B.jpg|thumb|left|NGR Class B]]
In 1906, six NGR [[South African Class 1 4-8-0|Class B]] [[4-8-0|{{nowrap|4-8-0}} Mastodon]] locomotives, designed by D.A. Hendrie, NGR Locomotive Superintendent from 1903 to 1910, were modified to a {{nowrap|4-8-2}} wheel arrangement by having trailing [[bissel truck]]s added below their cabs to improve their stability when hauling fast passenger trains. These [[South African Class 1B 4-8-2|altered Class B]] locomotives were the first {{nowrap|4-8-2}} tender locomotives in the world.<ref name="Holland 1"/>

The first locomotive to be designed and built as a {{nowrap|4-8-2}} tender locomotive was New Zealand's [[NZR X class|X class]], designed by [[Alfred Beattie]] and built by NZR's [[Addington Workshops]] in 1908. It was designed to haul heavy freight trains on the mountainous central section of the [[North Island Main Trunk]]. Some believed this was the source of the "Mountain" name of the {{nowrap|4-8-2}} type, although it is also possible that the name was originated by the [[Chesapeake & Ohio Railway]] in the United States, who named the type after the [[Allegheny Mountains]]. The X class was, however, not a typical Mountain type, since its trailing truck served to spread the axle load rather than to allow a larger and wider firebox. The trailing wheels were positioned well behind a narrow firebox, which itself sat above the coupled wheels, necessitating the same design compromise between coupled wheel diameter and grate size as on a [[2-8-0|{{nowrap|2-8-0}}]] Consolidation or {{nowrap|4-8-0}} Mastodon. A more common {{nowrap|4-8-2}} design was a progression of the classic [[4-6-2]] Pacific layout, which featured a wide firebox positioned above the trailing truck and behind the coupled wheels, allowing for a wide and deep firebox as well as large coupled wheels.<ref name="X Class">{{cite web |url=http://www.trainweb.org/nzsteam/x_class.html |title=Class X 4-8-2 |work=TrainWeb.org |access-date=2008-02-08}}</ref>

The NGR in 1909 placed in service the first example of the more common Mountain design, when it commissioned five [[South African Class 3 4-8-2|Class Hendrie D]] {{nowrap|4-8-2}} tender locomotives. It was designed by Hendrie to handle coal traffic on the upper Natal mainline and, while it was based on the Class Hendrie B {{nowrap|4-8-0}}, it had the firebox positioned to the rear of the coupled wheels to make a larger grate and ashpan possible. To accomplish this, the plate frame was equipped with a cast bridle at the rear to accommodate the improved firebox design, and the load also necessitated the addition of a trailing truck. Five locomotives were built by the [[North British Locomotive Company]] and delivered in 1909. The {{nowrap|4-8-2}} type went on to become the most widely used steam locomotive wheel arrangement in South Africa, with altogether thirty classes of both tank and tender versions eventually seeing service on the South African Railways.<ref name="Holland 1"/>