Uvalde Street Railway 0-4-2 Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class Progresso (Locobase 11375)

Data from "Steam Motors for Street Service", Railway and Locomotive Engineering,, Vol 23, No. 2 (February 1910), p. 66. See also H K Porter Company, Light Locomotives (Tenth Ed) (Pittsburgh, Pa: n.d, (1907?), pp.104-105, wire code Petale. (Thanks to Chris Hohl for his 11 August 2017 email referring to the original source, but noting some inaccuracies in Locobase's transcription of the data.) Works number was 4436 in October 1909.

This little tram motor worked the USR's streets as one of the very last "steam dummies" ordered by a US street railway. Its design had put its long cabin first with clerestory running along most of the roof; the small coal bunker trailedand was supported by a two-wheel truck. Hauling capacity on level grade was 610 tons. Steeper inclines reduced the load to 230 tons (1/2%), 140 tons (1%), 70 tons (2%), and 45 tons (3%).

Hohl and the 1907 catalogue persuaded Locobase that the Progresso did lead with its driving set rather than the unpowered single-axle truck as he had supposed.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID11375
RailroadUvalde Street Railway
Number in Class1
Road Numbers2
Number Built1
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)4
Engine Wheelbase (ft / m) 9.67
Ratio of driving wheelbase to overall engine wheelbase 0.41
Overall Wheelbase (engine & tender) (ft / m) 9.67
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)20,000 / 9072
Engine Weight (lbs / kg)28,500 / 12,927
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)
Tender Water Capacity (gals / ML)300 / 1.14
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 0.15
Minimum weight of rail (calculated) (lb/yd / kg/m)17 / 8.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)30 / 762
Boiler Pressure (psi / kPa)165 / 11.40
High Pressure Cylinders (dia x stroke) (in / mm)8" x 14" / 203x356
Tractive Effort (lbs / kg)4189 / 1900.10
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.77
Heating Ability
Tubes (number - dia) (in / mm)67 - 1.75" / 44
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m) 4.75 / 1.45
Firebox Area (sq ft / m2)32.50 / 3.02
Grate Area (sq ft / m2) 6.75 / 0.63
Evaporative Heating Surface (sq ft / m2)176 / 16.35
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)176 / 16.35
Evaporative Heating Surface/Cylinder Volume217.28
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation1114
Same as above plus superheater percentage1114
Same as above but substitute firebox area for grate area5363
Power L13448
Power MT760.15

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