Inside cylinders, a tall stack, twin thin safety valve columns, outside crank and side rods, and a frame girdling the boiler at midline characterized the locomotive as built. Eleven days after he began, Isaac Dripps had assembled the John Bull for a trial run, but regular operations didn't begin for two years because the road wasn't ready.
For most of its career, however, the John Bull looked quite different. The steam dome was moved forward to just behind the tall, spark-arresting stack. Engineers now rode in a large cab ahead of a covered tender.
More important, Stevens soon added a leading truck anchored to pins that extended from both ends of the lead axle. The frame extended well forward of the smokebox with the long "cowcatcher" probing still farther. The result was an apparatus that rose and fell like a helmet visor, but didn't not move side to side; the lead axle, however, now had 1" lateral play. To accommodate the frame, Stevens removed the coupling rods, which converted the John Bull to a 2-2-2-0, although the second "2" was of equal diameter to the driver.
Stevens claimed "uniform and complete" success with this innovation. In the 1832 report of the railroad, he reported a run with 10 cars (weight of stone and iron equivalent to 340 passengers) over the steepest grades and around the sharpest curves with no binding and reaching speeds of over 30 mph. Because the original alignment of the C&A was so smooth, level, and straight, the John Bull and sisters ran for nearly 30 years even at the reduced tractive effort afforded by the addition of the leading truck.
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||Camden & Amboy|
|Number in Class||4|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase|
|Overall Wheelbase (engine & tender)|
|Axle Loading (Maximum Weight per Axle)|
|Weight on Drivers||20000 lbs|
|Engine Weight||20000 lbs|
|Tender Light Weight|
|Total Engine and Tender Weight|
|Tender Water Capacity||1150 gals|
|Tender Fuel Capacity (oil/coal)||2 tons|
|Minimum weight of rail (calculated)||17 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||40 psi|
|Cylinders (dia x stroke)||9" x 20"|
|Tractive Effort||1020 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||19.61|
|Firebox Area||34.80 sq. ft|
|Grate Area||10.07 sq. ft|
|Evaporative Heating Surface||297 sq. ft|
|Combined Heating Surface||297 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||201.68|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||403|
|Same as above plus superheater percentage||403|
|Same as above but substitute firebox area for grate area||1392|