Locobase is intrigued by the unusual boiler pressure rating in these small Mountains. 213 psi converts to 15 bar (or atm), a unit of measure that was almost never used in North American railroading. In any event, these were small for their arrangement and had very low drivers, which suited the hilly terrain over which the class operated. They may have been the lightest 4-8-2s operating on the standard gauge anywhere in North America.
| Specifications | |
|---|---|
| Class | 551 |
| Locobase ID | 7347 |
| Railroad | Tennessee Central |
| Whyte | 4-8-2 |
| Road Numbers | 551-554 |
| Gauge | Std |
| Builder | Alco-Brooks |
| Year | 1926 |
| Valve Gear | Walschaert |
| Locomotive Length and Weight | |
| Driver Wheelbase | 16.75' |
| Engine Wheelbase | 37' |
| Ratio of driving wheelbase to overall engine wheebase | 0.45 |
| Overall Wheelbase (engine & tender) | 69.94' |
| Axle Loading (Maximum Weight per Axle) | |
| Weight on Drivers | 180500 lbs |
| Engine Weight | 273000 lbs |
| Tender Light Weight | 158800 lbs |
| Total Engine and Tender Weight | 431800 lbs |
| Tender Water Capacity | 9000 gals |
| Tender Fuel Capacity (oil/coal) | 14 tons |
| Minimum weight per yard of rail on which locomotive could run | 75.21 lb rail |
| Geometry Relating to Tractive Effort | |
| Driver Diameter | 63" |
| Boiler Pressure | 217.60 psi |
| Cylinders (dia x stroke) | 24" x 28" |
| Tractive Effort | 47350 lbs |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 3.81 |
| Heating Ability | |
| Firebox Area | 234 sq. ft |
| Grate Area | 59.95 sq. ft |
| Evaporative Heating Surface | 2795 |
| Superheating Surface | 752 |
| Combined Heating Surface | 3547 |
| Evaporative Heating Surface/Cylinder Volume | 190.64 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 13045.12 |
| Same as above plus superheater percentage | 15810.82 |
| Same as above but substitute firebox area for grate area | 61713.62 |
| Power L1 | 16726.79 |
| Power MT | 817.20 |
| This page last modified: . | [Contact] | All material © 1999-2008 SteamLocomotive.com |