Central Wharf 0-4-4 "Forney" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class unknown (Locobase 13880)

Data from "The Smallest Locomotive," English Mechanic & World of Science, No. 1004 (20 June 1884), p. 342. See also The Street Railway Journal, Volume 4, No 6 (June 1888). p. 150

The EMWS report described this Pensacola, Fla-based steam dummy in glowing terms, saying it "...attained a high rate of speed, pulls 15 loaded cars, weighing about 45 tons, and handles them easily." Crediting Master Mechanic John Douglass of the Central Wharf works, the report notes that the frame rode on two four-wheeled trucks, the leading one of which was powered. That truck was"... connected to an intermediate axle hung in the middle of the frame with a special bearing". Locobase imagines that this "intermediate axle" was a cross-piece linked through a member extending back from the truck and swiveling on the bearing. "This arrangement," claimed the report,"gives great freedom in passing the sharpest curves, and the long wheel base gives a steady motion to the engine on the track at a high rate of speed."

The Electric Railway Journal later revealed that this "Douglass-patent" design was being tested in several cities: "The Recent Test at Birmingham, of the Douglass patent small locomotive, proved entirely satisfactory, and the East Birmingham Iron Works are now building about twenty of these engines. Ten of them were ordered by the Cababa, Iron &

Railroad Company, and the remainder are being built for various firms in the south. Five are now in service at the Central Wharf, Pensacola, Florida."

Specifications by Steve Llanso of Sweat House Media
Locobase ID13880
RailroadCentral Wharf
Number in Class5
Road Numbers
Gauge20 in
Number Built5
Valve Gear
Locomotive Length and Weight
Driver Wheelbase 7.75'
Engine Wheelbase 7.75'
Ratio of driving wheelbase to overall engine wheebase1
Overall Wheelbase (engine & tender) 7.75'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers7000 lbs
Engine Weight7000 lbs
Tender Light Weight
Total Engine and Tender Weight7000 lbs
Tender Water Capacity180 gals
Tender Fuel Capacity (oil/coal)0.1 tons
Minimum weight of rail (calculated)6 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter12"
Boiler Pressure80 psi
Cylinders (dia x stroke)5" x 8"
Tractive Effort1133 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 6.18
Heating Ability
Firebox Area
Grate Area
Evaporative Heating Surface
Superheating Surface
Combined Heating Surface0
Evaporative Heating Surface/Cylinder Volume
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation0
Same as above plus superheater percentage0
Same as above but substitute firebox area for grate area0
Power L10
Power MT0

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