Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 15, p. 52. (Thanks to Chris Hohl for his 2 April 2021 email noting the correct road numbers.) Works numbers 9923 in April 1889 and 10359 in October.
This belt line encircled Chattanooga in a 50-mile (80 km) loop that had branches shooting off to the major Civil War battlesights at Lookout Mountain and east of the river. These tank engines duplicated the design of the first three engines (Locobase 11671) and lent their energies to passenger service on the street-railway portion. Although Connelly shows the pair with a single-axle trailing truck and 48" drivers, the original specs called for a bogie trailing truck and 46" wheels.
As with many street railways, steam traction was soon supplanted by electric power and the 22 went off to the Jackson Railroad in 1895 while the 20 was sold to Ducktown Sulpher, Copper & Iron Company in 1902.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | 22 |
| Locobase ID | 11605 |
| Railroad | Chattanooga Union |
| Country | USA |
| Whyte | 2-4-4T |
| Number in Class | 2 |
| Road Numbers | 22-23 |
| Gauge | Std |
| Number Built | 2 |
| Builder | Burnham, Williams & Co |
| Year | 1889 |
| Valve Gear | Stephenson |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 6.50 / 1.98 |
| Engine Wheelbase (ft / m) | 25.75 / 7.85 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.25 |
| Overall Wheelbase (engine & tender) (ft / m) | 25.75 / 7.85 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | |
| Weight on Drivers (lbs / kg) | 38,000 / 17,237 |
| Engine Weight (lbs / kg) | 65,000 / 29,484 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | 65,000 |
| Tender Water Capacity (gals / ML) | 900 / 3.41 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 32 / 16 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 46 / 1168 |
| Boiler Pressure (psi / kPa) | 130 / 900 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 12" x 20" / 305x508 |
| Tractive Effort (lbs / kg) | 6918 / 3137.96 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 5.49 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 114 - 2" / 51 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | 10.08 / 3.07 |
| Firebox Area (sq ft / m2) | 63.04 / 5.86 |
| Grate Area (sq ft / m2) | 12.70 / 1.18 |
| Evaporative Heating Surface (sq ft / m2) | 665 / 61.78 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 665 / 61.78 |
| Evaporative Heating Surface/Cylinder Volume | 253.82 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 1651 |
| Same as above plus superheater percentage | 1651 |
| Same as above but substitute firebox area for grate area | 8195 |
| Power L1 | 3729 |
| Power MT | 432.69 |