The latter 20 (numbered 1570-1589 from the start) came from Baldwin in 1926 (works numbers 58922, 58950, 58964-58966 in January, 59052-59058 in March, 59110-59113 in April, 59174-59177 in May).
Known as "Simple Simons" or "Simons" (according to C&O Power) because they operated as simple-expansion articulateds, unlike the earlier compound Mallets. Firebox had combustion chamber that added 145 sq ft (13.45 sq m) to direct heating surface area and the boiler had an Elesco K-54 feed water heater. When delivered, boilers were pressed at 205 psi. All four cylinders were supplied through 12" (305 mm) piston valves.
The Baldwin H-7as were credited with slightly higher weight on drivers, larger heating surface (6,580 sq ft). Cylinder horsepower for all was 4,092 hp.
By 1935, all of the H-7s were fitted with several thermic syphons that contributed a total of 165 sq ft (15.3 sq m) to the direct heating surface area. The result is shown in the specifications.
Alexander (American Locomotives, 1950) notes that H7 pulled 9,500-ton trains over 113-mile run from Russell, Kentucky to Columbus, Ohio in 5 hours. Averaged 4,400 miles per month until displaced by the 2-10-4s in Ohio and the 2-6-6-6 Alleghenies in the rest of the territory. 30 of the fifty were later leased to the Union Pacific. By then the fireboxes had been fitted with 167 sq ft of thermic syphon as shown in the specs."
|Specifications by Steve Llanso|
|Railroad||Chesapeake & Ohio (C & O)|
|Road Numbers||1100-1124/1540-1564, 1570-1589|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase||0.27|
|Overall Wheelbase (engine & tender)||104.70'|
|Axle Loading (Maximum Weight per Axle)||65200 lbs|
|Weight on Drivers||493070 lbs|
|Engine Weight||567500 lbs|
|Tender Light Weight||376340 lbs|
|Total Engine and Tender Weight||943840 lbs|
|Tender Water Capacity||21000 gals|
|Tender Fuel Capacity (oil/coal)||25 tons|
|Minimum weight of rail (calculated) on which locomotive could run||103 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||215 psi|
|Cylinders (dia x stroke)||23" x 32" (4)|
|Tractive Effort||108547 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.54|
|Firebox Area||632 sq. ft|
|Grate Area||112.20 sq. ft|
|Evaporative Heating Surface||6580 sq. ft|
|Superheating Surface||1849 sq. ft|
|Combined Heating Surface||8429 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||213.80|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||24123|
|Same as above plus superheater percentage||29430|
|Same as above but substitute firebox area for grate area||165774|