Note on the specifications: Chris Hohl's detailed table of differences compared the April 1884 data with data Locobase had obtained from another source that, regrettably, he didn't record. Responding to Hohl's comments, Locobase discovered the November 1886 discussion which included specifications furnished by direct communication from A J Stevens. The information included the comment that earlier specifications were based on blueprints and the set given in 1886 were "actual dimensions,weights, etc". Steven's data is used in Locobase's specs.
2nd Note on the specs: The tube heating surface area usually given (1,154 sq ft/107.21 sq m) seems to be based on the tubes' internal diameter. Although most North American railroads used the larger external (or "water side") figure, this "fire side" measurement wasn't completely unheard of in North America, but was much more common on European railways. Strong arguments could and were made in favor of either method.
Not a very successful engine and badly proportioned, but certainly big for her time. Master Mechanic AJ Stevens sought to get still more adhesive weight on the track by adding another axle.
Stevens installed valve gear of his own design -- the so-called monkey motion -- that included two valves for each cylinder. The Locomotive Engineers Journal article described it thusly:
"Each cylinder of the engine is fitted with two rotary-balanced valves, placed as near each end of the cylinder as possible, to save clearance of space that would otherwise be filled and exhausted uselessly by live steam. The valves are driven by the A. J. Stevens valve gear, employing but one eccentric on a side and reversing from the rocker."
The author then reported on the merits of this layout: "The Stevens valve motion has given great satisfaction where it has been used. For freight service especially it is greatly superior to the old link motion in the economical manner in which it handles steam at the shorter points of cut-off."
To give the long-wheelbase engine any hope of negotiating CP curves, the journal reported, "The engine truck is of the "swing-beam" order, allowing the center pin of the saddle to play an inch and a half each side of the center. The back pair of drivers have also a transverse play of one-half inch each way from the center line of the engine, which
reduces the rigid wheel base to the first and fourth axis. This allows the engine to take, a fifteen-degree curve, which is shorter than the maximum curve on the Central Pacific. The first, fourth and fifth pair of drivers have 'flanged tires, the second and third being blind."
Although it was steamed up and paraded in front of passengers, the engine simply was too big to be of much use at the time. Boiler tubes were much too short and total evaporative heating surface laughably meager. Possessed of one of the longest cylinder strokes ever put into a conventional steam locomotive, the engine's cylinder volume overwhelmed the boiler.
She was scrapped, it is believed, in 1894.
|Principal Dimensions by Steve Llanso of Sweat House Media|
|Number in Class||1|
|Locomotive Length and Weight|
|Driver Wheelbase (ft / m)||19.58 / 5.97|
|Engine Wheelbase (ft / m)||28.92 / 8.81|
|Ratio of driving wheelbase to overall engine wheebase||0.68|
|Overall Wheelbase (engine & tender) (ft / m)||52.65 / 19.94|
|Axle Loading (Maximum Weight per Axle) (lbs / kg)||26,750 / 12,134|
|Weight on Drivers (lbs / kg)||130,000 / 58,967|
|Engine Weight (lbs / kg)||154,000 / 69,853|
|Tender Loaded Weight (lbs / kg)||63,000 / 28,576|
|Total Engine and Tender Weight (lbs / kg)||217,000 / 98,429|
|Tender Water Capacity (gals / ML)||3000 / 11.36|
|Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)||5 / 4.50|
|Minimum weight of rail (calculated) (lb/yd / kg/m)||43 / 21.50|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in / mm)||57 / 1448|
|Boiler Pressure (psi / kPa)||135 / 9.30|
|High Pressure Cylinders (dia x stroke) (in / mm)||21" x 36" / 533x914|
|Tractive Effort (lbs / kg)||31,961 / 14497.28|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.07|
|Firebox Area (sq ft / m2)||197 / 18.30|
|Grate Area (sq ft / m2)||29.75 / 2.76|
|Evaporative Heating Surface (sq ft / m2)||1455 / 135.17|
|Superheating Surface (sq ft / m2)|
|Combined Heating Surface (sq ft / m2)||1455 / 135.17|
|Evaporative Heating Surface/Cylinder Volume||100.82|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||4016|
|Same as above plus superheater percentage||4016|
|Same as above but substitute firebox area for grate area||26,595|