The reference for locomotives and railcars


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Great Northern (US) class P-1
United States | 1914 | 15 produced
No. 1755 on a works photo
No. 1755 on a works photo
Ron Ziel, „American Locomotives 1858 to 1949”

The Great Northern was one of the first railroads in the United States to order Mountain locomotives. The manufacturer Lima saw these as Mikados, which had a two-axle forward bogie for better running characteristics in passenger service. The Great Northern wanted to use the P-1 to eliminate the need for helpers on passenger trains in Montana and the Cascades.

They had a conical boiler with a Belpaire firebox. The first ten P-1s were coal-fired and the last five were oil-fired. The diameter of the drivers was only 62 inches or 1,575 mm, which was an advantage on the steep lines. The speed of passenger trains was now 20 mph (32 km/h) on the 1.8 percent in Montana and 15 mph (24 km/h) on the 2.2 percent in the Cascades, both without helpers.

When these locomotives were no longer sufficient to meet the increased requirements, in 1928 all P-1s were rebuilt into 2-10-2 freight locomotives and designated class Q-2. The drivers and the cylinder diameter were each increased by one inch. The boiler only remained the same on the outside and had many changes on the inside, as well as a higher pressure. They were all coal-fired, but nine were converted to oil in the 1940s. Their decommissioning began in the 1950s and was completed in April 1958.

VariantP-1rebuilt Q-2
ManufacturerLimaSt. Paul
Axle config4-8-2 (Mountain) 2-10-2 (Santa Fé) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Wheelbase38 ft31 ft 4 in
Fixed wheelbase16 ft 9 in22 ft
Total wheelbase71 ft 4 in83 ft 6 1/2 in
Service weight326,000 lbs364,000 lbs
Adhesive weight218,000 lbs290,000 lbs
Total weight487,000 lbs679,600 lbs
Axle load55,000 lbs58,000 lbs
Water capacity8,000 us gal17,000 us gal
Fuel capacity30,000 lbs (coal)5,800 us gal (oil)
Power sourcesteam
Estimated power3,200 hp (2,386 kW)4,000 hp (2,983 kW)
Optimal speed33 mph
Starting effort61,911 lbf76,251 lbf
Power Plant
Driver diameter62 in63 in
Boiler pressure180 psi210 psi
Expansion typesimple
Cylinderstwo, 28 x 32 intwo, 29 x 32 in
Grate area78 sq ft
Firebox area340 sq ft362 sq ft
Tube heating area4,200 sq ft4,463 sq ft
Evaporative heating area4,540 sq ft4,825 sq ft
Superheater area975 sq ft1,184 sq ft
Total heating area5,515 sq ft6,009 sq ft
Calculated Values
steam locomotive
last changed: 04/2024

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