South Manchurian 4-6-2 Locomotives in Japan

Class 800 (Locobase 20190)

Data from Catalogue 10036--Locomotives for Export (New York City, April 1910), pp. 32-33. Works numbers were 44675-44681 in March 1908.

This class of Pacifics immediately followed the eighteen Ten-wheelers on Richmond's production line (Locobase 20193). Locobase notes in both entries that their common destination, identical boiler pressure and passenger-scaled driver diameter allow a direct comparison between a 4-6-0 and a 4-6-2 by the same builder in the same period of design transtion.

Here are some numbers: the Pacific weighed 19 tons more than the 4-6-0 but put a little less weight on the drivers; driving wheelbase was actually shorter, but the extra axle contributed to the 8 foot (2.44 m) longer engine wheelbase .Cylinder volume in the 4-6-2 increased by 20%, which was matched by the 25% increase in evaporative heating surface area and grate area by 56%, but the latter lay at the bottom of a wider firebox that was shorter and much shallower. As a result, the Pacific had slightly less total direct heating surface area.

Class 900 (Locobase 13137)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 60, p. 212. Works numbers were 51977, 51989-51990 in June 1919; 52022-52024 in July.

A large order of American locomotives for this railway included 20 American Locomotive Corporation Decapods, Baldwin Mikados, some switchers, and these Baldwin Pacifics. 11" piston valves fed the cylinders and the engines were generously superheated. 17 sq ft of arch tubes contributed to the direct heating surface.

The line over which these engines worked had 80-lb/yard (40-kg/metre) maximum grades of 1% on the main line and a 1 1/4% grade on a branch line. In accordance with an overall British influence on the SM, the engineer sat on the left side.

The Chosen Lines would procure even larger Pacfics a year later; see Locobase 13138.