Bahia 2-6-0 Locomotives in Brazil

Class 9 (Locobase 11787)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 10, p. 204 Works number ?? 1881.

Locobase cannot match this Mogul up with an entry in Connelly's Baldwin production list. The spec sheet says it was originally built for the Madura & Mamore in 1878.

The order also contains an internal contradiction. The heating surface area given for the tubes doesn't match up with the area calculated for 190 1 1/2" (38 mm) tubes each 7' 8 1/4" (2.35 m) long; the difference is 62 sq ft (5.75 sq m). If, however, the diameter was 1 5/8" (41 mm), the tube heating surface area would work out to be 622 sq ft (57.79 sq m).

So Locobase figures that the area given in the specs was calculated using the tube's inside diameter (fire side) for a couple of reasons and uses instead the water side: 1) Adding 3 mm to a 38mm tube is a reasonable thickness for boiler tubes of so small a diameter, 2) It is a way to rationalize what would otherwise be a mistake in calculation of two very clearly stated components of a cylinder's area.

Since Locobase chooses to use the water side measure in virtually all of the 16,000+ Locobase entries largely for historical rather than demonstrated superiority, he adopts that convention. He also concedes that the argument for and against water side vs fire side was never actually settled.