Data from "Atlantic Type for the C & O," Railway & Locomotive Engineering, Vol 15,(November 1902), p. 464
Firebox heating surface included 27.09 sq ft of water tubes. The design featured a "traction increaser" that could be applied to put an additional 12,000 lb on the drivers. The cab had the typical C & O clerestory on top. The only Atlantics on the Chesapeake and Ohio. The wheel arrangement may not seem the best choice for the line's profile and indeed these were the only 4-4-2s. But they held on for decades in their superheated form. (See 5048).Beginning with the last of the class, the Chessie's Atlantics were made over in the early 1920s. 278 was delivered in 1916 as shown above in the specs -- the other 19 were modified to match. Data from C & O's 1936 Locomotive Diagram book supplied by Allen Stanley in May 2005 from his extensive Rail Data Exchange.
Notice the choices made in the renovation. Tractive effort remained nearly identical because at the same time the cylinders gained a inch in diameter, the boiler pressure was knocked down 15 psi. Piston valves measured a healthy 12" in diameter. Weights increased considerably. Overall heating surface declined, but having 16.3% in superheater area could only improve efficiency. Firebox heating surface includes 23 sq ft in 4 arch tubes. The makeover must have been satisfactory as 13 of the engines remained in use until 1949
| Principal Dimensions by Steve Llanso of Sweat House Media | ||
|---|---|---|
| Class | A-16 | A-16s |
| Locobase ID | 5047 | 5048 |
| Railroad | Chesapeake & Ohio (C&O) | Chesapeake & Ohio (C&O) |
| Country | USA | USA |
| Whyte | 4-4-2 | 4-4-2 |
| Number in Class | 20 | 20 |
| Road Numbers | 275-294 | 275-294 |
| Gauge | Std | Std |
| Number Built | 20 | |
| Builder | Alco-Schenectady | Alco |
| Year | 1902 | 1902 |
| Valve Gear | Stephenson | Walschaert |
| Locomotive Length and Weight | ||
| Driver Wheelbase (ft / m) | 7 / 2.13 | 7 / 2.13 |
| Engine Wheelbase (ft / m) | 27.50 / 8.38 | 27.92 / 8.51 |
| Ratio of driving wheelbase to overall engine wheebase | 0.25 | 0.25 |
| Overall Wheelbase (engine & tender) (ft / m) | 55.29 / 16.85 | 57.04 / 17.39 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 58,500 / 26,535 | |
| Weight on Drivers (lbs / kg) | 93,000 / 42,184 | 113,500 / 51,483 |
| Engine Weight (lbs / kg) | 173,000 / 78,472 | 199,500 / 90,492 |
| Tender Loaded Weight (lbs / kg) | 136,310 / 61,829 | |
| Total Engine and Tender Weight (lbs / kg) | 335,810 / 152,321 | |
| Tender Water Capacity (gals / ML) | 6000 / 22.73 | 7000 / 26.52 |
| Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT) | 9 / 8.20 | 12.50 / 11.40 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 78 / 39 | 95 / 47.50 |
| Geometry Relating to Tractive Effort | ||
| Driver Diameter (in / mm) | 72 / 1829 | 73 / 1854 |
| Boiler Pressure (psi / kPa) | 200 / 13.80 | 185 / 12.80 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 21" x 26" / 533x660 | 22" x 26" / 559x660 |
| Tractive Effort (lbs / kg) | 27,073 / 12280.12 | 27,107 / 12295.54 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 3.44 | 4.19 |
| Heating Ability | ||
| Firebox Area (sq ft / m2) | 207.79 / 19.31 | 201 / 18.68 |
| Grate Area (sq ft / m2) | 50.32 / 4.68 | 50.20 / 4.67 |
| Evaporative Heating Surface (sq ft / m2) | 3506 / 325.84 | 2470 / 229.55 |
| Superheating Surface (sq ft / m2) | 480 / 44.61 | |
| Combined Heating Surface (sq ft / m2) | 3506 / 325.84 | 2950 / 274.16 |
| Evaporative Heating Surface/Cylinder Volume | 336.38 | 215.92 |
| Computations Relating to Power Output (More Information) | ||
| Robert LeMassena's Power Computation | 10,064 | 9287 |
| Same as above plus superheater percentage | 10,064 | 10,773 |
| Same as above but substitute firebox area for grate area | 41,558 | 43,135 |
| Power L1 | 10,465 | 15,338 |
| Power MT | 496.16 | 595.85 |