Chicago, Burlington & Quincy 4-8-2 "Mountain" Locomotives of the USA

In 1922, the Chicago, Burlington & Quincy Railroad's passenger trains needed heavier power and it ordered and received eight 4-8-2s (road numbers 7000 through 7007) from the Lima Locomotive Works. These Class B-1 "Mountains" had 27 x 30 cylinders, 74" driver, a boiler pressure of 200 psi, a tractive effort of 50,240 lbs and a weight of 364,000 pounds. All eight were designed to burn lignite.

The Baldwin Locomotive Works delivered thirteen Class B-1a "Mountains" in 1925. These locomotives were assigned road numbers 7008 through 7020 and were similar to the Class B-1s. Seven were designed to burn lignite and the other six were equipped to burn bituminous coal.

By 1953, all of the Class B-1s and most of the B-1a locomotives were scrapped. The last Class B-1a was scrapped in 1955.

Roster by Richard Duley

ClassRoad NumbersYear BuiltBuilder

Class Details by Steve Llanso of Sweat House Media

Class B-1 (Locobase 2901)

Data from Corbin & Kerka (1960) and Data from locomotive diagram published on Vernon Beck's website -- (accessed 22 March 2003). Works numbers were 6248-6255 in September-October 1922.

Lima delivered eight of these Mountains for the heaviest express service without doubleheading. Equipped with healthy amount of superheater area, 14" (356 mm) piston valves, Worthington No 4 feed water heaters, Duplex automatic stokers and fitted for lignite burning. The combustion chamber contributed 105 sq ft (9.75 sq m) and the four arch tubes 34.5 sq ft (3.2 sq m) to the direct heating surface area.

See Verne L Munger, "In My Own Words: Running in the Blizzard", Trains Magazine, Vol 74, No 1 (January 2014), pp. 58-61, in which Munger describes a grueling day as fireman on 7007on 1 January 1949 as it worked the Ravenna-Alliance (Neb) section in a mounting blizzard that brought every other train to a complete stop. The last of these retired in the mid-1950s.

Class B-1A (Locobase 5474)

Corbin & Kerka (1960) and Data from locomotive diagram published on Vernon Beck's website -- (accessed 22 March 2003). DeGolyer, Volume 76, pp. 242+. Works numbers were 58482-58483 in June 1925, 58509-58515 in July, and 58602-58605 in August.

Baldwin's 13 B-1As in 1925 were split into seven lignite-burners (7008-7014) and six bituminous coal consumers (2015-2020). The lignite burners had 5/16" (7.9 mm) openings in the grate. The firebox heating surface was augmented by four arch tubes aggregating 34.2 sq ft (3.2 sq m) and a combustion chamber contributing 107 sq ft. (9.95 sq m). The 14"(356 mm) piston valves were only average in size. The class also had heat-treated alloy steel running gear and a Worthington #4 feed water heater.

7017 later received roller bearings on the valve gear and three were refitted with roller bearings on the driving wheel axles. (14, 18, & 20).

The last of these retired in the mid-1950s.

Specifications by Steve Llanso of Sweat House Media
Locobase ID2901 5474
RailroadChicago, Burlington & Quincy (CB&Q)Chicago, Burlington & Quincy (CB&Q)
Number in Class813
Road Numbers7000-70077008-7020
Number Built813
Valve GearWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft)19.2519.25
Engine Wheelbase (ft)41.6341.63
Ratio of driving wheelbase to overall engine wheebase 0.46 0.46
Overall Wheelbase (engine & tender) (ft)81.42
Axle Loading (Maximum Weight per Axle) (lbs)
Weight on Drivers (lbs)248,050249,140
Engine Weight (lbs)381,400376,440
Tender Loaded Weight (lbs)205,300247,000
Total Engine and Tender Weight (lbs)586,700623,440
Tender Water Capacity (gals)10,00012,000
Tender Fuel Capacity (oil/coal) (gals/tons)2018
Minimum weight of rail (calculated) (lb/yd)103104
Geometry Relating to Tractive Effort
Driver Diameter (in)7474
Boiler Pressure (psi)210210
High Pressure Cylinders (dia x stroke) (in)27" x 30"27" x 30"
Tractive Effort (lbs)52,75452,754
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.70 4.72
Heating Ability
Firebox Area (sq ft)376.80387
Grate Area (sq ft)78.2578.25
Evaporative Heating Surface (sq ft)43564263
Superheating Surface (sq ft)11721256
Combined Heating Surface (sq ft)55285519
Evaporative Heating Surface/Cylinder Volume219.11214.43
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation16,43316,433
Same as above plus superheater percentage19,88320,212
Same as above but substitute firebox area for grate area95,74599,962
Power L121,87122,801
Power MT777.54807.06



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