Pine Belt Lumber Company 2-8-2 "Mikado" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 8 (Locobase 14313)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 52, p. 377. Works number was 42491 in September 1915.

Like many other Mikados of very similar dimensions, this was a logging engine (although the Baldwin specs describe the service as "freight"). Pine Belt of Towson, Oklahoma chose a relatively large logging 2-8-2 to satisfy some stringent requirements.

The specification details allow us to examine operations on a well-built road with demanding features. The 8 rolled on 56 lb/yard (28 kg/metre) rail on what the specs describe as "an exceptionally good logging road." There were "practically no curves" on the main line. Yet, the specs caution, the boiler and the running gear must "be made of a heavy pattern commensurate with the severe requirements obtaining in this case." Indeed, the specs emphasize later, "Springs and spring rigging to be designed for very rough service, and to be extremely heavy throughout for engine and tender."

(Kenneth L Smith's Sawmill, p.76, tells us that the profile laid out in the following paragraphs resulted when the PBLC "employed an inept surveyor who put the main road up a hill with a grade so steep the log train couldn't climb it.")

Notes tell us the 8 was destined for 7-9 miles (11.3-14.5 km) of "a very hilly division with principally velocity grades so that every advantage will be taking in running for the hills." Among other competencies, therefore, would be an ability to handle the cars downhill at speeds of at least 25 mph (40.25 km/h).

A baseline value for the 8's capacity was seven 35-ton loaded cars (245 tons) up a 4% for 400 feet (122 metres).

Then the buyer's worst case ran as follows: The train would head down a 3% grade about 1,000 ft (305 metres) long "into a hollow". Then immediately the train headed up another 3% grade combined with a 10 degree curve (radii 574 feet/175 metres) for 800 feet (2,625 metres), 3 1/2% for 200 feet (61 metres), 2% for 300 feet (92 metres), 4% for 300 feet. No relief in sight because the climb continued as "a straight pull of about 2 miles (3.2 km) on a straight grade of 1 1/2% to 2%". The train then headed down a grade of equal severity and length.

Enough was enough when the train got to the 5% grade that measured 3/4 of mile (3,960 feet/1,207 metres), the specs conceded: "On this hill, they figure on doubling." There was more. The boiler's design had to ensure that the crown sheet would be covered by at least 2 inches (51 mm) of water when the locomotive operated up the two 9 1/2% grades, each of which measured 200 feet long (61 metres).

The 8 would later work for the W R Pickering Lumber Company of Shelby County, Texas. The lumbering ended in 1931 and the 120,000 acres of timber lay untouched. 73,700 of those acres would later be incorporated into the Sabine National Forest for $2.82 an acre.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID14,313
RailroadPine Belt Lumber Company
Number in Class1
Road Numbers8
Number Built1
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.08 / 3.99
Engine Wheelbase (ft / m)27 / 8.23
Ratio of driving wheelbase to overall engine wheebase 0.48
Overall Wheelbase (engine & tender) (ft / m)55 / 16.76
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)135,000 / 61,235
Engine Weight (lbs / kg)178,000 / 80,740
Tender Loaded Weight (lbs / kg)80,000 / 36,287
Total Engine and Tender Weight (lbs / kg)258,000 / 117,027
Tender Water Capacity (gals / ML)4000 / 15.15
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)6 / 5.50
Minimum weight of rail (calculated) (lb/yd / kg/m)56 / 28
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)48 / 1219
Boiler Pressure (psi / kPa)160 / 11
High Pressure Cylinders (dia x stroke) (in / mm)20.5" x 28" / 521x711
Tractive Effort (lbs / kg)33,340 / 15122.79
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.05
Heating Ability
Firebox Area (sq ft / m2)158 / 14.68
Grate Area (sq ft / m2)41.30 / 3.84
Evaporative Heating Surface (sq ft / m2)3166 / 294.13
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)3166 / 294.13
Evaporative Heating Surface/Cylinder Volume295.98
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation6608
Same as above plus superheater percentage6608
Same as above but substitute firebox area for grate area25,280
Power L14734
Power MT309.23

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