See Locobase 10026 for a full description of mine locomotives. Of the three detailed in Appleton's Cyclopedia, this was definitely Papa Bear. Clearly, it was intended for larger-scale mining operations and was about as big as a four-wheel mine locomotive was likely to get.
This was the smallest of a series of low-slung steamers that roved among the shores and chambers of gold and other mineral mines. A study of the illustration in Appleton's Cyclopedia (Illus 299 on page 340) shows a roofed and cased engine with the stack just above the shroud forward and the controls set relatively low.
A typical tunnel would be 4 ft wide from the bed to 18" above and tapering to 2 1/2 ft at the top, which was about 5 1/2 ft above the bed. Appleton's reported that one customer's gold mine at Forest City, Calif had a tunnel running 4,000 ft into the mountain and a 20"-gauge T-rail track. Grades ran as steep as 20 ft to the mile (4.2%) and curves arced in radii of between 60-150 ft.
The locomotive's trailing load rode in 4-wheel cars with a tare weight of 750 lb and a capacity of 2 tons; the cars rolled on 12" wheels that were spaced 20" apart.
See Mark Aldrich's Safety First (1997) for accounts of just how dangerous operating in such tight confines could easily prove to be.
Also note the following commentary from the Report of the Geological Survey of Ohio (Nevins & Myers, 1884), p. 342:
"The first trials of mine locomotives were made in Pennsylvania, in the anthracite coal fields, but they are now found in all the coal mining states. As compared with stationary machinery and wire ropes, they hold their own, but they are objected to by many on account of the smoke and gas generated from the coal. In the hands of an intelligent mining engineer, who is master of the art of mine ventilation, they can be used with perfect safety, but taken where uneducated and unskilled men control the mining department, they are dangerous forces, and their introduction has frequently led to fatal consequences."
Amen. The Survey's authors follow with their recommendations for ameliorating the hazard:
"Wherever mine locomotives are used, it is necessary for the health and safety of the miners to ventilate the workings with air, which is not allowed to come in contact with the current amidst which the locomotive moves, and a column of wind of 25,000 cubic feet per minute, and moving at the rate of 5 miles per hour is required to rid the mine of smoke and keep the galleries in a fit state for miners to occupy."
Locobases 10027 & 10028 have specifications of two slightly larger locomotives.
See Locobase 10026 for a full description of mine locomotives. This was the middle-sized bear of the three described in Appleton's Cyclopedia.
|Specifications by Steve Llanso of Sweat House Media|
|Class||Mine locomotive - 10""||Mine locomotive - 8""||Mine locomotive - 9""|
|Number in Class|
|Gauge||20 in||20 in||20 in|
|Builder||Burnham, Parry, Williams & Co||Burnham, Parry, Williams & Co||Burnham, Parry, Williams & Co|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase||1||1||1|
|Overall Wheelbase (engine & tender)||5'||3.83'||4'|
|Axle Loading (Maximum Weight per Axle)|
|Weight on Drivers||23000 lbs||15000 lbs||18000 lbs|
|Engine Weight||23000 lbs||15000 lbs||18000 lbs|
|Tender Light Weight|
|Total Engine and Tender Weight||23000 lbs||15000 lbs||18000 lbs|
|Tender Water Capacity||180 gals||200 gals||300 gals|
|Tender Fuel Capacity (oil/coal)|
|Minimum weight of rail (calculated)||19 lb/yard||13 lb/yard||15 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||115 psi||115 psi||115 psi|
|Cylinders (dia x stroke)||10" x 14"||8" x 12"||9" x 12"|
|Tractive Effort||4562 lbs||2502 lbs||3167 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||5.04||6.00||5.68|
|Firebox Area||38.50 sq. ft||24 sq. ft||30 sq. ft|
|Grate Area||8 sq. ft||5 sq. ft||4.50 sq. ft|
|Evaporative Heating Surface||323 sq. ft||129 sq. ft||164 sq. ft|
|Combined Heating Surface||323 sq. ft||129 sq. ft||164 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||253.80||184.78||185.61|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||920||575||518|
|Same as above plus superheater percentage||920||575||518|
|Same as above but substitute firebox area for grate area||4428||2760||3450|