In 1911, the B & O ordered a special 2-6-8-0 by mating one of its E-24 Consolidations (Locobase 4786) to a new front boiler and engine set that contained a feedwater heater with 369 2" tubes of much shorter length (8 feet 3 inches) and a total heating service area of 1,594 sq ft. The LP cylinders under this boiler section had 34" diameters.
The same problems with slipping and uneven traction encountered by other users of the 2-6-8-0 arrangement led to no other such engines and the KL-1 was converted back to a 2-8-0 in 1917.
A two-batch class of pushers that varied primarily in their weights. The first batch -- 7020-7039 -- put 461,000 lb on the rail while the last 10 weighed 5 tons more. Delivered with slide valves actuated by Walschaert gear feeding the low-pressure cylinders, the engines later received piston valves on those big cans; these were actuated by Baker gear.
According to Drury (1993), these big engines proved "slow and complicated". Still many served throughout World War Two before being scrapped in 1949-1950. Several were rebuilt as EL-4 class 2-8-8-0s.
The first standard-gauge Mallet built in the United States, this helper engine was jointly designed by the B&O's James E Muhlfield and Alco's Carl J. Mellin. Old Maud, so called after a comic-strip mule, proved an immediate success on the B&O's western Pennsylvania grades. Her scrapping came only in 1938.
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||Baltimore & Ohio (B&O)||Baltimore & Ohio (B&O)||Baltimore & Ohio (B&O)|
|Number in Class||1||30||1|
|Road Numbers||2421||2401-2420, 2422-2431/7020-7049||2400/7000|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase||0.42||0.37||0.33|
|Overall Wheelbase (engine & tender)||77.23'||64.58'|
|Axle Loading (Maximum Weight per Axle)||50800 lbs||63400 lbs|
|Weight on Drivers||309800 lbs||471900 lbs||334565 lbs|
|Engine Weight||326850 lbs||471900 lbs||334565 lbs|
|Tender Light Weight||143370 lbs||196000 lbs||206400 lbs|
|Total Engine and Tender Weight||470220 lbs||667900 lbs||540965 lbs|
|Tender Water Capacity||7000 gals||12000 gals||7000 gals|
|Tender Fuel Capacity (oil/coal)||15 tons||12.5 tons||15 tons|
|Minimum weight of rail (calculated)||74 lb/yard||98 lb/yard||93 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||205 psi||210 psi||235 psi|
|High Pressure Cylinders (dia x stroke)||22" x 28"||26" x 32"||20" x 32"|
|Low Pressure Cylinders (dia x stroke)||34" x 28" (2)||41" x 32" (2)||32" x 32" (2)|
|Tractive Effort||59447 lbs||98352 lbs||65664 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||5.21||4.80||5.10|
|Firebox Area||184.35 sq. ft||321.50 sq. ft||219 sq. ft|
|Grate Area||49 sq. ft||100 sq. ft||72.20 sq. ft|
|Evaporative Heating Surface||2847 sq. ft||5641 sq. ft||5585 sq. ft|
|Superheating Surface||1002 sq. ft|
|Combined Heating Surface||2847 sq. ft||6643 sq. ft||5585 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||231.10||286.87||480.00|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||10045||21000||16967|
|Same as above plus superheater percentage||10045||24150||16967|
|Same as above but substitute firebox area for grate area||37792||77642||51465|