The reference for locomotives and railcars


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Pennsylvania class I
later class H1
United States | 1875 | 545 produced

After Baldwin's first Consolidation locomotives were not well received by American railroads, this wheel arrangement had a breakthrough in 1875 when the PRR made it its standard freight locomotive. It started with Class I, which later became Class H1. A total of 545 of these were produced in the PRR's own factories in Altoona.

Curve negotiation was guaranteed by the fact that only the first and last driving axles had wheel flanges. The special thing about the firebox was that its ceiling sloped backwards. However, this arrangement made it difficult for the crews to set the correct water level in the boiler during operation. The later H2 thus received the Belpaire firebox, which was soon used as standard on the PRR.

Gary Rauch / prr.railfan.net

Despite the difficulties with the firebox, these locomotives regularly pulled 80 to 90-car freight trains at 14 mph. Because of their pulling power, they were also called “Modocs” after the Modoc Indians. Later, 57 were converted to class B5 with a 4-6-0 wheel arrangement.

Builtfrom 1875
Axle config2-8-0 (Consolidation) 
Gauge4 ft 1 1/2 in (Narrow gauge)
Dimensions and Weights
Length58 ft 4 5/8 in
Wheelbase22 ft 1 in
Fixed wheelbase13 ft 8 in
Total wheelbase48 ft 10 3/8 in
Empty weight85,200 lbs
Service weight92,700 lbs
Adhesive weight80,500 lbs
Total weight160,190 lbs
Axle load22,200 lbs
Water capacity3,000 us gal
Fuel capacity12,000 lbs (coal)
Power sourcesteam
Estimated power475 hp (354 kW)
Optimal speed15 mph
Starting effort20,400 lbf
Power Plant
Driver diameter50 in
Boiler pressure125 psi
Expansion typesimple
Cylinderstwo, 20 x 24 in
Grate area23 sq ft
Firebox area92 sq ft
Tube heating area1,166 sq ft
Evaporative heating area1,258 sq ft
Total heating area1,258 sq ft
Calculated Values
steam locomotive
last changed: 11/2023

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