Mammoth Cave 0-4-2 Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class Hercules (Locobase 13288)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 32, p. 10. See also the National Park Service account at, last accessed 21 October 2011. Works number was 33075 in December 1908.

This rear-tank engine repeated the design of the quartet of steam dummies that operated between Atlanta and Decatur for the Metropolitan Railway. Hercules was used to pull one or two cars (75-80 short tons) up a 3 1/2% grade and around 14- and 17-degree curves (82- and 68-metres/269- and 223-ft radii, respectively). Such was the route between Bell's Station (then the Louisville & Nashvile's Glasgow Junction) to the Mammoth Cave Hotel. The big attraction, of course, was the vast complex of underground connections, estimated to amount to the greatest underground mileage in the world at 392 miles.

The railroad opened in November 1886. According to the NPS: "Although functional, the rail service on this line seems to have inspired some skepticism on the part of travelers following the rugged line around curves and over trestles through rough country. One passenger, in 1907, described the line as 'two streaks of rust' with grass growing in between. The same writer recounts that the conductor pointed out: 'You notice that we have our cowcatcher on the rear end, so as to keep the cows out of the ladiesÆ coach. Why, a bull got after us last week and would have ketched us, too, if we hadnÆt been on the down grade!'"

Although the L & N took over management, competition from automobiles steadily eroded ridership. In 1928, the railroad was sold to new owners who decided to close the line and sell off the assets in 1931.

Specifications by Steve Llanso of Sweat House Media
Locobase ID13288
RailroadMammoth Cave
Number in Class1
Road Numbers3
Number Built1
BuilderBurnham, Williams & Co
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase5'
Engine Wheelbase 9.25'
Ratio of driving wheelbase to overall engine wheebase 0.54
Overall Wheelbase (engine & tender) 9.25'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers34000 lbs
Engine Weight40000 lbs
Tender Light Weight
Total Engine and Tender Weight
Tender Water Capacity500 gals
Tender Fuel Capacity (oil/coal)
Minimum weight of rail (calculated)28 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter39"
Boiler Pressure130 psi
Cylinders (dia x stroke)12" x 18"
Tractive Effort7344 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.63
Heating Ability
Firebox Area25.48 sq. ft
Grate Area10.10 sq. ft
Evaporative Heating Surface314 sq. ft
Superheating Surface
Combined Heating Surface314 sq. ft
Evaporative Heating Surface/Cylinder Volume133.27
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation1313
Same as above plus superheater percentage1313
Same as above but substitute firebox area for grate area3312
Power L11583
Power MT205.29


If you have any railroad data such as diagram books, rail station plans or anything else that you would be willing to share, please contact us.