Baltimore & Ohio 4-2-0 "Jervis" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class Lafayette (Locobase 2542)

Data from Alvin F Staufer, Steam and Electric Locomotives of the Baltimore and Ohio (Medina, OH: Alvin F Staufer, 1964), p. 6. "Old Time Locomotive Performances", Railway Age, Volume 22 (25 December 1896), pp. 507. See also the original letter from William Norris dated 3 April 1837 and published in American Railroad Journal and Advocate of Internal Improvments, Volume VI [6], No 14 (8 April 1837), p. 210; and Leonard Kernan, Table K-3- "Steam Engines used on railroads in the District of Baltimore", Office of the Secretary of the Treasury, "Steam Engines", House of Representatives Document 21, 13 December 1838 (25th Congress - 3rd Session), - ) , p. 207. (Thanks to Chris Hohl for his 22 March 2018 email directing me to Staufer's diagram and for noting the tender's weight, capacity, and the original engine number.)

Based on the Philadelphia & Columbia's Washington County Farmer, this engine was a typical William Norris design. It had the Bury "haystack" boiler, a bar (vs plate) frame, and a valve gear that was cam-operated. Hollingsworth (1982) notes that later engines in the class had a more typical "gab" motion.

An 1838 US Government report credited the Lafayette with a "high" pressure boiler (the other option was "low pressure") and generating 12-15 horsepower. The "Steam Engines" report covered every kind of steam engine--stationary, railroad, marine--then in use in the United States. It's quite a snapshot of the first generation of the industrial revolution in the US.

The weights given in Locobase's data are those reported by William Norris in his 1837 letter to the American Railroad Journal. Staufer's diagram shows higher values of 18,030 lb (8,178 kg) on the drivers, 28,200 lb (12,791 kg) for the engine. Locobase notes an interesting discrepancy betwen the two sets of figures. Norris's engine weight is nearly identical to Staufer's adhesion weight and his adhesion weight is almost identical to Staufer's "front truck" weight. Could Norris have misstated his own weight distributions or could Staufer's weights have come from the replica described as built according to the original specifications?

Hollingsworth contends that these engines were a great success, being reliable and showing markedly reduced fuel consumption. William Norris, whose 3 April 1837 report on his locomotives is reproduced in the 1896 article, certainly agreed. He described in detail tests that demonstrated pulling power that he claimed was typical of every-day results:

"The La Fayette is performing daily on the Columbia railway, and any persons can, at any time, see for themselves the immense powers of this engine. She drags with ease 25 loaded cars, over abrupt curves and high grades, and on a rise of 52 feet per mile, with the actual weight of 241,275 pounds [120.6 short tons or 109.4 metric tons] (taken from the weighmaster's books), attached to her; she has come to a dead stand, and started again without the least difficulty in a state of rest. On Friday last, March 31, this engine brought in, attached to her, the unprecedented and enormous load of 45 cars, 25 of which were loaded, and this load she carried over the grade of 52 feet rise per mile, without any difficulty, not a single instant's delay, but steadily at the rate of nearly 9 miles per hour [14.5 kph]."

With reason, Norris closed by challenging: "Let unbelievers come and see for themselves."

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID2542
RailroadBaltimore & Ohio (B&O)
Number in Class8
Road Numbers13
Number Built8
BuilderWilliam Norris
Valve Gear
Locomotive Length and Weight
Driver Wheelbase (ft / m)
Engine Wheelbase (ft / m) 9.40 / 2.87
Ratio of driving wheelbase to overall engine wheelbase
Overall Wheelbase (engine & tender) (ft / m)29 / 8.84
Axle Loading (Maximum Weight per Axle) (lbs / kg)18,030 / 8178
Weight on Drivers (lbs / kg)11,375 / 5160
Engine Weight (lbs / kg)18,725 / 8494
Tender Loaded Weight (lbs / kg)11,820 / 5361
Total Engine and Tender Weight (lbs / kg)30,545 / 13,855
Tender Water Capacity (gals / ML)500 / 2.27
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 0.70 / 1
Minimum weight of rail (calculated) (lb/yd / kg/m)19 / 9.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)48 / 1219
Boiler Pressure (psi / kPa)90 / 6.20
High Pressure Cylinders (dia x stroke) (in / mm)10.5" x 18" / 267x457
Tractive Effort (lbs / kg)3163 / 1434.71
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.60
Heating Ability
Tubes (number - dia) (in / mm)56 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m) 7.83 / 2.39
Firebox Area (sq ft / m2)33.80 / 3.14
Grate Area (sq ft / m2) 5.60 / 0.52
Evaporative Heating Surface (sq ft / m2)265 / 24.62
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)265 / 24.62
Evaporative Heating Surface/Cylinder Volume147.22
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation504
Same as above plus superheater percentage504
Same as above but substitute firebox area for grate area3042
Power L11736
Power MT336.46

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Wes Barris