The "Mikado" type locomotives on the Missouri Pacific Railroad were considered to be excellent locomotives and for the most part performed better than most of that type used by American Railroads, but they did have limits. The MoPac 2-8-2s with about 67 square feet of grate area had limits with regard to sustaining steaming capacity. The Lima Locomotive Work's introduction of the "Super Power" 2-8-4s attracted the attention of the MoPac. However, it decided to give an order in 1928 to the American Locomotive Company for five 2-8-4s to be used on its International-Great Northern.
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 International-Great Northern Railroad, part of the Missouri Pacific
system, purchased five "Berkshire" type locomotives from the American
Locomotive Company in 1928. These locomotives were designated as Class
BK-63 and were given road numbers 1121 through 1125.
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
Class BK-63 (Locobase 50)
Data from Lloyd Stagner (Trains, November 1988), which augments the data from the 1930 Locomotive Cyclopedia. See also MP's 1953ca Locomotive Diagrams book supplied in May 2005 by Allen Stanley from his extensive Raildata collection. (Thanks to Chris Hohl for his 7 April 2015 email correcting the tender's weights, fuel capacity, and booster power.) Works numbers were 67656-67660 in November 1928.
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.
Class BK-63 (Locobase 1371)
Follow-ons to the Alcos of 1928 (Locobase 50
) with these differences: 2 sand domes, full-length frame, Worthington BL feedwater heaters. Works numbers were 7476-7500.
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.