The Missouri Pacific Railroad decided to purchase twenty-five more "Berkshire" type locomotives in 1930 and this time opted to give the order to the Lima Locomotive Works. These twenty-five locomotives were designated as Class BK-63 and were assigned road numbers 1901 through 1925. They had 63" diameter drivers, 28" x 30" cylinders, a 240 psi boiler pressure, they exerted 66,500 pounds of tractive effort and each weighed 412,200 pounds.
The Motive Power Department of the Missouri Pacific established a high standard for appearance and utility in the locomotives it used. The "Berkshires" that were ordered were remarkably handsome. They followed the basic dimensions of the A-1 as used on the Boston & Albany, but had some very noticeable differences.
The MoPac did not feel that 100 square feet of grate was needed, so the firebox was shortened by 18 inches and the boiler tubes were lengthened. This alteration reduced the grate area to 88.3 square feet, but increased total evaporative surface to 5,413 square feet and allowed a 219 square feet increase in super heater surface.
Also featured was Walshaert valve gear, Lima used Baker gear on all of it other locomotives, an outside journal lead truck and a delta trailing truck. These modifications made these locomotives weigh eight tons more than the ones used on the B&A. The tenders, with the characteristic MoPac doghouse, were a little longer and they carried 17,000 gallons of water and twenty tons of coal, a combination, which made the loaded tender some thirteen tons heavier than the ones on the B&A.
There are no surviving MoPac 2-8-4 "Berkshire" type locomotives
The Class BK-63 locomotives were, for the most part, similar to all the other Berkshires built by ALCO and had 63" diameter drivers, 28" x 30" cylinders, a 240 psi boiler pressure, they exerted 69,400 pounds of tractive effort and each weighed 404,000 pounds. They were delivered as coal burners with a 100.3 sq. ft. grate area, but were later converted to burn oil.
There are no surviving I-GN 2-8-4 "Berkshire" type locomotives
|Railroad||Class||Qty.||Road Numbers||Year Built||Builder||Notes|
|International-Great Northern||BK-63||5||1121-1125||1928||ALCO||Numbers 1121-1125 scrapped in 1953-1954|
|Missouri Pacific||BK-63||25||1901-1925||1930||Lima||Numbers 1901-1925 scrapped in the early 1950s|
Originally built for International-Great Northern subsidiary as 1121-1125, these were among the first wave of Berkshires. Firebox had two thermic syphons contributing 105 sq ft (9.75 sq m) to the direct heating surface area, valve motion had limited cutoff (60%) and operated 14" (356 mm) piston valves. Other goodies included the Worthington B1 feedwater heater, Chambers front-end throttle, Alco Type G power reversing gear, Franklin trailing-truck booster, and Dupont Simplex mechanical stoker. Stagner gives a firebox heating surface, including syphons, of 383 sq ft (35.6 sq m), which is the figure given in the 1936 MP diagram.
Stagner notes that they shared an uncluttered look with Chicago & North Western Berks bought in the same year. Their service on the "Jenny", which had mainlines from Longview, Texas to Palestine-San Antonio-Laredo and Palestine-Houston-Fort Worth. The design's lack of a combustion chamber concerned some.
Firebox had 92 sq ft (8.5 sq m) in two thermic siphons, valve motion had limited cutoff.
Similar to several other 2-8-4 classes built in the same half decade. These were converted to 75"-drivered 4-8-4s in 1940-1942.
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||International Great Northern (MP)||Missouri Pacific (MP)|
|Number in Class||5||25|
|Locomotive Length and Weight|
|Driver Wheelbase (ft)||16.80||16.80|
|Engine Wheelbase (ft)||42||42|
|Ratio of driving wheelbase to overall engine wheebase||0.40||0.40|
|Overall Wheelbase (engine & tender) (ft)||86.23||86.23|
|Axle Loading (Maximum Weight per Axle) (lbs)|
|Weight on Drivers (lbs)||267,500||267,500|
|Engine Weight (lbs)||404,000||412,000|
|Tender Loaded Weight (lbs)||306,580||310,980|
|Total Engine and Tender Weight (lbs)||710,580||722,980|
|Tender Water Capacity (gals)||15,000||15,000|
|Tender Fuel Capacity (oil/coal) (gals/tons)||5650||18|
|Minimum weight of rail (calculated) (lb/yd)||111||111|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in)||63||63|
|Boiler Pressure (psi)||240||240|
|High Pressure Cylinders (dia x stroke) (in)||28" x 30"||28" x 30"|
|Tractive Effort (lbs)||76,160||76,160|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||3.51||3.51|
|Firebox Area (sq ft)||427||383|
|Grate Area (sq ft)||100.30||100.30|
|Evaporative Heating Surface (sq ft)||5118||5116|
|Superheating Surface (sq ft)||2121||2121|
|Combined Heating Surface (sq ft)||7239||7237|
|Evaporative Heating Surface/Cylinder Volume||239.38||239.29|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||24,072||24,072|
|Same as above plus superheater percentage||31,053||31,053|
|Same as above but substitute firebox area for grate area||132,199||118,577|