Utah Railway 2-8-8-0 "Consolidation Mallet" Locomotives in the USA

In 1918, Utah Railway received three 2-8-8-0 locomotives, ordered in late 1916 by the Union Pacific Equipment Association. Utah Railway had asked for UP's assistance in the design of these locomotives, with Utah Railway soon to assume the operation of its own trains. UP evaluated the available designs, and determined that the design of fifteen B&O EL-series delivered in 1916 was a good match for the projected and similar service slow speed coal drags on Utah Railway. These three Utah Railway locomotives were very similar to later UP's MC-class, but were built by Baldwin and were about 12,000 pounds lighter (weight on drivers) than the sixteen locomotives delivered in 1918 to UP and OSL. Utah Railway used MC-2 as the class for their locomotives, the same as UP's class. The Utah Railway three 2-8-8-0s, numbered as 200-202, were delivered in April and June 1918, being built by Baldwin rather than ALCo. The first UP 2-8-8-0 locomotives, numbered as UP 3600-3618, were built by ALCo-Schenectady in May 1918.

Information provided by Steve Low.


Class Details by Steve Llanso of Sweat House Media

Class 200 (Locobase 9496)

Data from "Mallet Locomotives for the Utah Railway," Railway and Locomotive Engineering, February 1919, p.39. See also DeGolyer, Volume 56, pp. 249+. (Thanks to Steve Low for his 18 March 2018 email underscoring the UR trio's design origins.) Works numbers were 48221-48222 in April 1918 and 48901 in June.

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. Steve Low noted that the UR asked for the Union Pacific's help in selecting the best design for their particular requirements. It was the UP that spotlighted the EL-series as the best fit. Low adds that the 200 class strongly resembled the later MC class (e.g. Locobase 7466) procured by the Union Pacific.

One small difference was the UR engines' use of 1" (25.4 mm) 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.

All four cylinders were supplied through 15" (381 mm) piston valves. Firebox heating surface area included 43 sq ft (4.0 sq m) in four arch tubes and 118 sq ft (10.96 sq m) from the combustion chamber.

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."

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.

Principal Dimensions by Steve Llanso of Sweat House Media
Class200
Locobase ID9496
RailroadUtah Railway
CountryUSA
Whyte2-8-8-0
Number in Class3
Road Numbers200-202
GaugeStd
Number Built3
BuilderBaldwin
Year1918
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)15.50 / 4.72
Engine Wheelbase (ft / m)50.33 / 15.34
Ratio of driving wheelbase to overall engine wheebase 0.31
Overall Wheelbase (engine & tender) (ft / m)88.50 / 26.97
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)452,300 / 205,160
Engine Weight (lbs / kg)476,300 / 216,046
Tender Loaded Weight (lbs / kg)215,700 / 97,840
Total Engine and Tender Weight (lbs / kg)692,000 / 313,886
Tender Water Capacity (gals / ML)12,000 / 45.45
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)20 / 18.20
Minimum weight of rail (calculated) (lb/yd / kg/m)94 / 47
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)57 / 1448
Boiler Pressure (psi / kPa)210 / 14.50
High Pressure Cylinders (dia x stroke) (in / mm)26" x 32" / 660x813
Low Pressure Cylinders (dia x stroke) (in / mm)41" x 32" / 1041x813
Tractive Effort (lbs / kg)96,627 / 43829.32
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.68
Heating Ability
Firebox Area (sq ft / m2)392 / 36.43
Grate Area (sq ft / m2)88.20 / 8.20
Evaporative Heating Surface (sq ft / m2)5835 / 542.29
Superheating Surface (sq ft / m2)1446 / 134.39
Combined Heating Surface (sq ft / m2)7281 / 676.68
Evaporative Heating Surface/Cylinder Volume296.73
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation18,522
Same as above plus superheater percentage22,226
Same as above but substitute firebox area for grate area98,784
Power L18490
Power MT331.06

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