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 |
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 Rail Data Exchange. (Thanks to Chris Hohl for his 7 April 2015 email correcting the tender's weights, fuel capacity, and booster power; a 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error. His 14 March 2018 supplied the Alco builder's card for Order No S-1624 of December 1928.) 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.Valve motion had limited cutoff (60%) and operated 14" (356 mm) piston valves. Other goodies included the Worthington 4 1/2 BL feedwater heater, Chambers front-end throttle, Alco Type G power reversing gear, Franklin trailing-truck booster, and Dupont Simplex mechanical stoker.
The builder's card showed that the class was delivered as coal burners and trailed 285,600 lb (129,546 kg) tenders carrying 18 tons (16.3 metric tons) of coal and the 15,000 gallons of water shown. Hohl notes that the conversion to oil burning was not long in coming, taking place in 1931-1933.
Direct heating surface areas vary from source to source. Locomotive Cyclopedia's figure of 427 sq ft (39.67 sq m) included two thermic syphons contributing 105 sq ft (9.75 sq m) and 31 sq ft of arch tubes.Stagner used a later firebox heating surface, including 92 sq ft (8.55 sq m) of syphons but deleting arch tubes, of 383 sq ft (35.6 sq m), which is the figure given in the 1936 MP diagram. Locobase adopted the figures in the builder's card Chris Hohl supplied, which include 103 sq ft (9.57 sq m) of syphons and 21 sq ft (1.95 sq m) of arch tubes.
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.
Data from "Class 284-S-412", Negative Order No. 1120 datacard, Lima Locomotive Works. See also George H Drury, Guide to North American Steam Locomotives (rev ed) (Waukesha, WI:Kalmbach Books, 2015), p. 220; and Brian Solomon, North American Locomotives: A Railroad-by-Railroad Photohistory (Beverly, MA: Voyageur Press, 2012), p. 172. (Many thanks to Chris Hohl for his 28 October 2019 email supplying the datacard that had the correct data for this class.)Works numbers were 7476-7484 in May 1930, 7485-7492 in June, 7493-7500 in July.
Follow-ons to the International Great NorthernAlcos of 1928 (Locobase 50) with these differences: two sand domes, full-length frame, Worthington BL feedwater heaters. Surprisingly graceful proportions and lines led Brian Solomon to described the class's look as "unusually handsome."
Firebox had 100.5 sq ft (9.34 sq m) in two thermic siphons, valve motion cutoff was limited to 60%, which yielded 69,400 lb (31,479 kg or 308.71 kN) and a 3.97 factor of adhesion.
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; see Locobase 1372.
| Principal Dimensions by Steve Llanso of Middle Run Media | ||
|---|---|---|
| Class | BK-63 | BK-63 |
| Locobase ID | 50 | 1371 |
| Railroad | International-Great Northern (MP) | Missouri Pacific (MP) |
| Country | USA | USA |
| Whyte | 2-8-4 | 2-8-4 |
| Number in Class | 5 | 25 |
| Road Numbers | 1121-1125 | 1901-1925 |
| Gauge | Std | Std |
| Number Built | 5 | 25 |
| Builder | Alco-Schenectady | Lima |
| Year | 1928 | 1930 |
| Valve Gear | Walschaert | Walschaert |
| Locomotive Length and Weight | ||
| Driver Wheelbase (ft / m) | 16.80 / 5.12 | 16.75 / 5.11 |
| Engine Wheelbase (ft / m) | 42 / 12.80 | 40.42 / 12.32 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.40 | 0.41 |
| Overall Wheelbase (engine & tender) (ft / m) | 86.23 / 26.28 | 85.06 / 25.93 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | ||
| Weight on Drivers (lbs / kg) | 267,500 / 121,336 | 275,500 / 124,965 |
| Engine Weight (lbs / kg) | 404,000 / 183,252 | 412,000 / 186,880 |
| Tender Loaded Weight (lbs / kg) | 306,580 / 139,063 | 310,980 / 141,058 |
| Total Engine and Tender Weight (lbs / kg) | 710,580 / 322,315 | 722,980 / 327,938 |
| Tender Water Capacity (gals / ML) | 15,000 / 56.82 | 17,250 / 65.34 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 5650 / 21,385 | 20 / 18 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 111 / 55.50 | 115 / 57.50 |
| Geometry Relating to Tractive Effort | ||
| Driver Diameter (in / mm) | 63 / 1600 | 63 / 1600 |
| Boiler Pressure (psi / kPa) | 240 / 1650 | 240 / 1650 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 28" x 30" / 711x762 | 28" x 30" / 711x762 |
| Tractive Effort (lbs / kg) | 76,160 / 34545.64 | 76,160 / 34545.64 |
| Booster (lbs) | 13,200 | |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 3.51 | 3.62 |
| Heating Ability | ||
| Tubes (number - dia) (in / mm) | 84 - 2.25" / 57 | 84 - 2.25" / 57 |
| Flues (number - dia) (in / mm) | 204 - 3.5" / 89 | 204 - 3.5" / 89 |
| Flue/Tube length (ft / m) | 20 / 6.10 | 21.50 / 6.55 |
| Firebox Area (sq ft / m2) | 415 / 38.55 | 357 / 33.17 |
| Grate Area (sq ft / m2) | 100.30 / 9.32 | 87.90 / 8.17 |
| Evaporative Heating Surface (sq ft / m2) | 5118 / 475.65 | 5414 / 502.97 |
| Superheating Surface (sq ft / m2) | 2121 / 197.12 | 2330 / 216.46 |
| Combined Heating Surface (sq ft / m2) | 7239 / 672.77 | 7744 / 719.43 |
| Evaporative Heating Surface/Cylinder Volume | 239.38 | 253.23 |
| Computations Relating to Power Output (More Information) | ||
| Robert LeMassena's Power Computation | 24,072 | 21,096 |
| Same as above plus superheater percentage | 31,053 | 27,425 |
| Same as above but substitute firebox area for grate area | 128,484 | 111,384 |
| Power L1 | 30,978 | 33,202 |
| Power MT | 1021.23 | 1062.76 |
