Utah Railway 2-8-8-0 "Consolidation Mallet" Type Locomotives

Class 200 (Locobase 9496)

Data from "Mallet Locomotives for the Utah Railway," Railway and Locomotive Engineering, February 1919, p.39.

Virtually identical to the B & O ELs shown in Locobase 439, this trio went to the United States Smelting company for them to operate on the UR. One small difference was the UR engines' use of 1" smaller diameter drivers to conquer grades of up to 2.4%. The Mallet layout contributed to an ability to negotiate 20-deg curves in sidings and 9-deg curves on the main line.

The article noted another feature of use in the Utah Railway's winding surroundings: "The Baldwin design of flexible articulated frame connection is used. With this construction, the front and rear frames can move relatively to each other in a vertical plane, without causing binding at the hinge pin. The value of this feature is specially noticeable in a Mallet locomotive with long wheelbase, when passing over uneven tracks or sudden changes in grade."

Steam was admitted through 15" piston valves on all cylinders.

The design proved successful enough to endure into the 1950s with two of the engines leaving service in 1954 and the third (201) as late as March 1957.

Specifications
Class200
Locobase ID9496
RailroadUtah Railway
Whyte2-8-8-0
Road Numbers200-202
GaugeStd
BuilderBaldwin
Year1918
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase15.50'
Engine Wheelbase50.33'
Ratio of driving wheelbase to overall engine wheebase 0.31
Overall Wheelbase (engine & tender)88.50'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers452300 lbs
Engine Weight476300 lbs
Tender Light Weight215700 lbs
Total Engine and Tender Weight692000 lbs
Tender Water Capacity12000 gals
Tender Fuel Capacity (oil/coal)20 tons
Minimum weight per yard of rail on which locomotive could run94.23 lb rail
Geometry Relating to Tractive Effort
Driver Diameter57"
Boiler Pressure210 psi
Cylinders (dia x stroke)26" x 32"
Low Pressure Cylinders (dia x stroke)41" x 32"
Tractive Effort96627 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.68
Heating Ability
Firebox Area392 sq. ft
Grate Area88.20 sq. ft
Evaporative Heating Surface5835
Superheating Surface1446
Combined Heating Surface7281
Evaporative Heating Surface/Cylinder Volume296.73
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation18522
Same as above plus superheater percentage22200.45
Same as above but substitute firebox area for grate area98668.68
Power L18489.86
Power MT331.05

Credits

Introduction and specifications provided by Steve Llanso of Sweat House Media.