The reference for locomotives and railcars
Chesapeake & Ohio class H-7
United States | 1923 | 45 produced
Former C&O No. 1123 as Richmond, Fredericksburg & Potomac No. 2
Former C&O No. 1123 as Richmond, Fredericksburg & Potomac No. 2
collection Taylor Rush

After various Mallets with the wheel arrangement 2-6-6-2, the C&O had the class H-7 built with the wheel arrangement 2-8-8-2. In 1923 and 1924, 25 H-7s were delivered by ALCO and in 1926 20 H-7a by Baldwin followed, which had a slightly higher adhesive weight. Since, unlike their predecessors, they worked with simple expansion, they were called “Simple Simons”.

By 1935 they received a boiler pressure of now 215 instead of 205 psi and thermic syphons. The 632 square foot firebox heating area now included 145 square feet from the combustion chamber and 165 from the thermic syphons. They could haul a 9,500 short tons freight train 113 miles in five hours.

They were replaced on the flatter lines by the class T-1 2-10-4s and on hilly lines by the 2-6-6-6 “Alleghenies”. 30 of the 45 locomotives were later leased to the Union Pacific. The Richmond, Fredericksburg & Potomac also bought some locomotives.

ManufacturerALCO, Baldwin
Axle config2-8-8-2 (Mikado Mallet) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Wheelbase58 ft 1 in
Fixed wheelbase15 ft 9 in
Total wheelbase104 ft 8 1/2 in
Service weight567,500 lbs
Adhesive weight493,070 lbs
Total weight943,840 lbs
Axle load65,200 lbs
Water capacity21,000 us gal
Fuel capacity50,000 lbs (coal)
Power sourcesteam
Estimated power4,850 hp (3,617 kW)
Optimal speed28 mph
Starting effort108,547 lbf
Power Plant
Driver diameter57 in
Boiler pressure215 psi
Expansion typesimple
Cylindersfour, 23 x 32 in
Grate area112.2 sq ft
Firebox area632 sq ft
Tube heating area5,948 sq ft
Evaporative heating area6,580 sq ft
Superheater area1,849 sq ft
Total heating area8,429 sq ft
Calculated Values
steam locomotive
last changed: 07/2023

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