The reference for locomotives and railcars


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US Railroad Administration Heavy Mountain
Chesapeake & Ohio class J-2 and Norfolk & Western class K2
United States | 1918 | 15 produced
No. 137 on a works photo
No. 137 on a works photo
Edwin P. Alexander, „American Locomotives 1900 to 1950”

One of the USRA standard types intended for lighter, fast freight trains was the Heavy Mountain. Compared to the Light Mountain, it had the same wheel diameter and boiler pressure, but a cylinder diameter increased by one inch. Compared to the Mikados, which were also intended for lighter freight trains, they had a driver diameter that was seven inches larger and were therefore designed for higher speeds.

Only 15 of the Heavy Mountain were built, five of which were built as the class J-2 of the Chesapeake & Ohio and ten as the class K2 of the Norfolk & Western. A total of 37 copies were built in 1923 and 1926, differing in details from the USRA standard design. The Norfolk & Western's twelve K-2a already had higher boiler pressure and larger drivers.

VariantChesapeake & OhioNorfolk & Western K-2a
ManufacturerALCO, Baldwin
Axle config4-8-2 (Mountain) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Wheelbase40 ft
Fixed wheelbase18 ft 3 in
Total wheelbase75 ft 8 1/2 in
Service weight352,500 lbs359,460 lbs
Adhesive weight243,000 lbs248,150 lbs
Total weight546,700 lbs738,060 lbs
Axle load60,750 lbs62,040 lbs
Water capacity10,000 us gal
Fuel capacity32,000 lbs (coal)
Power sourcesteam
Estimated power3,600 hp (2,685 kW)3,900 hp (2,908 kW)
Optimal speed40 mph
Starting effort57,948 lbf62,832 lbf
Power Plant
Driver diameter69 in70 in
Boiler pressure200 psi220 psi
Expansion typesimple
Cylinderstwo, 28 x 30 in
Grate area76.3 sq ft
Firebox area373 sq ft369 sq ft
Tube heating area4,293 sq ft4,101 sq ft
Evaporative heating area4,666 sq ft4,470 sq ft
Superheater area1,085 sq ft
Total heating area5,751 sq ft5,555 sq ft
Calculated Values
steam locomotive
last changed: 11/2023

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