Class J (Locobase 4854)

Data from C&NW 10 - 1952 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 52697-52706 in June 1913, 54520-54525 in April 1914, 55562-55567 in March 1916, and 56284-56293 in November.

The Omaha division actually was part of the Chicago & NorthWestern Railway, but it ordered and serviced its own locomotives. Even so, most of its classes were very similar to NorthWestern engines. This set of Js were virtually identical to the C&NW Js (Locobase 6306) , says Larry Bohn, author of the website members.lsol.net/mollyandmic/c393.htm. The only differences were the number of digits in the number and a missing horizontal cross-bar in the Omaha Js' cab windows.

Firebox heating surface included 29.6 sq ft (2.75 sq m) of arch tubes.

Most of the class was rebuilt in 1937-1938 and redesignated Class J-A; see Locobase 16523.

Class J (Locobase 6306)

Data from C & NW 10 - 1952 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Firebox heating surface included 29.6 sq ft of arch tubes. Data from diagram. The first 192 delivered used Baker valve gear, the remainder moved steam with the Young gear, which had two rods, two links and allowed cutoffs to be set as high as 90% of stroke.

This class was the backbone of freight work on the Chicago & North Western. Many later saw a major increase in superheater area; see Locobase 8383.

Delivered over a period of 10 years, the class remained in widespread service well into the 1950s.

Class J-2 (Locobase 8385)

Data from C&NW 10 - 1952 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Schenectady works numbers were 61034-61037 in April 1919 and Richmond's works numbers were 62609-62614 in January 1921.

These were classic USRA Heavy Mikado engines (Locobase 41) with a slight difference in tube count. Schenectady delivered four in April 1919, but Richmond's six followed almost two years later in January 1921.

Schenectadies used Standard stokers while the Richmonds had Modified Bs. Firebox heating surface area included 27 sq ft (2.51 sq m) of arch tubes. Piston valves had 14"(356 mm) diameters.

Class J-3 (Locobase 9)

Data from 1930 Locomotive Cyclopedia of Ameican Practice (New York: Simmons-Boardman Publishing Co, 1930), p. 111. (Many thanks to Chris Hohl for his 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error .) Works numbers 67091-67092 in October 1926, and 67093-67098 in November.

According to [] (last accessed 1 June 2006), these were modernized USRA Heavy Mikados (Locobase 41) with Delta cast-steel trailing trucks, Type E superheater, and an exhaust steam injector. One remarkable feature of this class was the single diameter of tube used in the boiler - all 232 tubes measured 3 1/2" each.

432-435 were fitted with thermic syphons that added 84 sq ft (7.8 sq m) to the firebox heating surface in addition to the 14.3 sq ft (1.33 sq m) that remained of the arch tubes. This raised total direct heating surface from 307 sq ft to the 368.3 sq ft (28.5 sq m) shown in the specs. Steam entered the cylinders through 14" (356 mm) piston valves.

These Mikes saw steam out on the Chicago & North Western. Firebox heating surface includes 27 sq ft (2.5 sq m) of arch tubes.

Class J-A (Locobase 8383)

Data from C & NW 10 - 1952 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

This renovation of the original J (Locobase 6306) design saw a substantial increase in its superheater area as well as an increase in driver diameter. A few surrendered their arch tubes in favor of circulators. The 51 sq ft of the latter device increased the firebox heating surface to 281 sq ft. Subsidiary St Paul, Minneapolis & Omaha rebuilt many of its J-class locomotives (at least 23 of the 32, as far as Locobase can tell). These had exhaust-steam injectors.

Class J-A-C (Locobase 16523)

Data from C&W 10 - 1952 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Locobase 4854 describes the 1913 batch of 32 Mikados delivered to the Omaha Road. Beginning in the mid-1930s, the railroad substantially modified more than half the class (and one C&NW engine as 440) with very little impact on weights. The firebox, already of adequate size, remained essentially untouched except for the addition of a Standard B-K stoker.

The boiler exchanged dozens of small tubes for nine more flues and 25% more superheater area. Boiler pressure increased by just over 1 atmosphere (15 psi). Taller drivers, all eight of Boxpok design, allowed faster running thanks to the internal counterweighting. Exhaust injectors preheated the water.