Missouri Pacific 4-8-4 "Northern" Locomotives in the USA

Class 2101/N-75 Victory Locomotives (Locobase 1372)

Data from 1956 Missouri Pacific Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also "Missouri Pacific Rebuilds Locomotives", Railway Mechanical Engineer, Volume 115, No 9 (September 1941), pp. 354-359, (Thanks to Chris Hohl for correcting the valve gear ID.)

Rebuilt 2-8-4s (Locobase 1371) that became very successful freight engines whose tall drivers turned on roller bearings. Feed water heater was the Worthington 4 1/4 BL-2. The firebox heating surface area includes the combustion chamber, 113 sq ft (10.5 sq m) in two thermic syphons (one in the combustion chamber, one in the firebox proper), and 15 sq ft (1.4 sq m) of arch tubes.

See [] (visited 7 January 2003), where Wes Barris says they had cast-steel beds and roller bearings. In 2019, Locobase found the RME article cited above which confirms Barris's report and goes on to note that "practially

complete boilers were constructed at the Sedalia shops ...". In addition, "new [General Steel Castings] cast-steel bdd frames with integral cylinders [were] applied, also new and larger driving wheels, roller bearings, new valve gear and rods, and larger tenders installed."

In June 1941, seven of the class amassed 75,288 miles/121,213 km (10,755 miles (17,316 km)/locomotive), 2.61 times the mileage the original Berkshires had been able to reach.

Class N-73 (Locobase 266)

Data from 1947 Locomotive Cyclopedia tables and MP 7 - 1956 - Locomotive Diagrams supplied in May 2005 from his extensive collection. See also "4-8-4 Cousins", Trains (December 1943), p. 29. (Thanks to Chris Hohl for his 9 February 2018 email including the Trains article and pointing out the tender's loaded weight.) Works numbers were 69714-69728 in 1943.

Firebox heating surface included 136 sq ft (12.6 sq m) of thermic syphons installed in the firebox itself and the combustion chamber. These freight engines were based on the Denver and Rio Grande Western's 1800-class 4-8-4s, with a little Northern Pacific A-5 blended in. Compared to the 2100-class rebuilds (Locobase 1371) of 1940-1942, these Northerns had smaller drivers and less cylinder volume, but a higher boiler pressure setting. Their axles turned on Timken roller bearings and, like the 2100s, 14" (356 mm) piston valves supplied the cylinders. Feed water was heated by a Worthington 6 - 5A.

The last of the class was scrapped in 1956.

Another 4-8-4 class on the MP's roster were the 2101-2125, which were rebuilds from 63-in DD 2-8-4 Berkshires to 75-in driver 4-8-4s. (See Locobase 1372).