US Railroad Administration Light Mountain
Missouri Pacific class MT-69, Nashville, Chattanooga & St. Louis class J1-54, New Haven class R-1, and Southern Railway (USA) class Ts-1
United States 1918 47 produced
The USRA Light Mountain was planned as a light standard freight locomotive and had a boiler slightly larger than that of the Heavy Pacific or the Heavy Mikado. It was almost 20,000 pounds lighter than the Heavy Mountain, had cylinders that were an inch smaller in diameter, and the same driver diameter. A total of 47 were built, with the Southern Railway getting the most at 25. The rest went to the Missouri Pacific, the Nashville, Chattanooga & St. Louis, and the New Haven. By 1930, 90 more copies had been built.
Technical data
General
- Built
- 1918
- Manufacturers
- ALCO, Baldwin
- Wheel arrangement
- 4-8-2 (Mountain)
- Gauge
- 1,435 mm (Standard gauge)
Dimensions and weights
- Wheelbase
- 12.19 m
- Total wheelbase
- 23.08 m
- Service mass
- 148.3 t
- Adhesion mass
- 101.8 t
- Total mass
- 236.2 t
- Rigid wheelbase
- 5.56 m
- Axle load
- 25.6 t
- Water capacity
- 37,854 l
- Fuel capacity
- 14.5 t (coal)
Boiler
- Grate area
- 6.531 m²
- Firebox surface
- 32.33 m²
- Tube heating surface
- 350.524 m²
- Evaporative heating surface
- 382.854 m²
- Superheater surface
- 89.744 m²
- Total heating surface
- 472.6 m²
Power plant
- Driver diameter
- 1,753 mm
- Boiler pressure
- 13.8 bar
- Expansion type
- simple expansion
- Cylinders
- two, 686 x 762 mm
Power
- Power source
- steam
- Estimated power
- 2,424 kW (3,296 PS)
- Starting effort
- 239.7 kN
Calculated values
- Factor of adhesion
- 1 : 4.17
- Optimal speed
- 61 km/h
- Power-to-weight ratio
- 16.3 kW/t
- Heating Surface Equivalent
- 724.0 m²
- Cylinder volume/HSE
- 1 : 777.56
- Adhesive weight/Total
- 1 : 1.46
- Tractive force/Heating surface
- 1 : 10.59
- Grate area/Heating surface
- 1 : 72.36
- Firebox/Tube surface
- 1 : 10.84
- Total/Superheater
- 1 : 4.27
