Chicago, Rock Island & Pacific 2-8-2 "Mikado" Locomotives in the USA

Class K-55 (USRA) (Locobase 7231)

Data from RI to 1951Locomotive Diagrams Combined supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

As part of the USRA's distribution of Light Mikados (Locobase 40), Baldwin built the first nine of the Rock Island's batch of 20 and Alco produced the latter eleven. Locobase has several examples of as-built light Mikes, so this entry shows the Rock's firebox reconditioning in which 28 sq ft (2.6 sq m) of arch tubes was replaced by 77 sq ft (7.15 sq m) of thermic syphons.

Class K-60 (Locobase 2796)

Data from W J Tollerton, "Recent Power for the Rock Island Lines", Railway Age Gazette, Volume 56, No 2 (9 January 2014), pp. 86-88. See also DeGolyer, Volume 40, p. 196 and Volume 47, pp. 87. Baldwin works numbers were 37750-37756, 37766-37770 in May 1912; 37846-37853, 37874-37877, 37883-37888, 37924-37933 in June; 40045-40058, 40085 in June 1913; 40135-40144 in July. Alco's Schenectady works numbers were 51170-51179 in July 1912 and 58285-58304 in October 1913.

The first of the Rock's Mikados, these engines were built by the two major builders Baldwin and American Locomotive Company's Schenectady Works:

48 more followed after World War I; see Locobases 7232-7233.

Piston valves were of a generous 16" (406 mm) diameter and the engines were delivered with brick arches and 29 sq ft (2.69 sq m) of arch tubes. Locobase can't say if the choice of outside radial valve gear was made by the railroad or the builder. As the table shows, all of Alco's locomotives came equipped with Walschaert's gear and Baldwin fitted theirs with Baker-Pilliod valve gear.

Baker gear was very new to the locomotive industry and Baldwin's specifications records show that the initial installations required adjustments. A "Hereafter" note written in the first Baldwin batch's specs and inspired by T Romney's 1 July 1912 letter advised Baldwin (and through them, Pilliod Company, the Baker valve manufacturer): "Avoid making side set in reverse lever rod by connecting the power reverse rod on the inside arm of the reverse shaft, below the attachment for the rod which runs forward to the valve motion."

The second batch incorporated this request as supplemental 166 ()volume 47, p. 96). supplemental 167 added that some portions of the valve gear had only a 1/8" (3.2 mm) clearance at full travel and previous rods had "too much spring."

WJ Tollerton, Chief Mechanical Superintendent wrote in in the RAG that they'd proven to be "excellent steamers; there is experienced no difficulty in maintaining full boiler pressure at all times and the absence of black smoke at the stack is evidence of their boiler efficiency." When adjusted properly, the air and screw reverses "lighten[ed[ the work of the engineer [giving] him a better opportunity to more carefully regulate the cut-off." The fireman's job felt easier because in most instances, he needed only to reach back as far as the coal gate for a full scoop of coal.

Red ball (i.e. fast) or drag (slow) freights proved equally amenable to improvements in efficiency thanks to these locomotives. Per 1000 gross ton miles(565 metric ton/km) on the Herington-Pratt, Kansas section (126 miles at a ruling grade of 0.8%), the Mikes dropped coal consumption from 96 lb (27.05 kg/km) to 66 lb (18.6 kg/km) compared to the earlier 2-8-0s while raising the average train load from 1,650 tons to 2,400 tons.

Tenders held either 16 tons (14.5 metric tons) of coal or 3,200 to 4,400 US gallons (12,113 or 16,654 litres) of oil. Boiler pressure in these engines began at 180 psi (12.4 bar); the earlier ones were raised to 190 psi and later engines were delivered at 200-210 psi. Many had firebox updates in which the arch tubes were replaced by 82 sq ft (7.62 sq m) of thermic syphons, which increased direct heating surface to 361 sq ft (33.54 sq m). Some even received roller bearings.

Clearly a prized workhorse, the Mikados soldiered on to the end of steam on the Rock.

Class MP-63e, f/K-57/K-64 (Locobase 7232)

Data from RI to 1951 Combined Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also "Mikado, Santa Fe, and Mountain Type Locomotives for the Chicago, Rock Island and Pacific Railway", Railway and Locomotive Engineering, Volume 34, No 2 (February 1921), pp. 33-35. (Thanks to Chris Hohl for his 8 February 2019 email and article link noting differences in original steam pressure and tender capacity.) Works numbers were 62152-62161 in October 1920 and 63169-63181 in December 1921.

The Rock Island continued building after World War I a line of Mikados that it first procured in 1912 (Locobase 2796), but wrought several important changes. Both the direct heating surface and the superheater surface areas were increased, the former being accomplished by including 116.7 sq ft (10.84 sq m) of Nicholson thermic syphons and the latter by increasing the number of flues. The postwar class of 48 can be further subdivided by the number of tubes and a consequent difference in evaporative heating surface. The first two batches, which arrived in 1920 and 1922, were as shown in the specs. The last 24 are depicted in Locobase 7233.

Class MP-63g, h, j/K-57/K-64 (Locobase 7233)

Data from RI to 1951 Combined Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.Works numbers were 64150-64179 in February 1923 (63g,h) and 64647-64676 in September (63j).

The run of Mikados that began in 1912 (Locobases 2796 and 7232) came to its conclusion in 1923, Brooks rang one more change on the boiler, deleting ten more tubes in favor of two more superheater flues. Thus this class had a still higher percentage of superheater area in relation to overall heating surface. The firebox heating surface remained the same and still included 116.7 sq ft (10.84 sq m) of thermic syphons.

The Rock Island later raised the boiler setting to 200 psi, which raised tractive effort and changed the road's designator to K-64.

The remaining 2-8-2 batches would feature several changes; see Locobases 11 and 7223.

Class MP-63k/K-64B (Locobase 11)

Data from 1930 Locomotive Cyclopedia and RI to 1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (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 were 66926-66935 in June 1926.

Firebox heating surface area included 82 sq ft (7.62 sq m) of thermic syphons, which represented a further 34 sq ft (3.16 sq m) reduction in such supplemental appliances. These were the last in a series of Brooks-built Mikado classes delivered to the Rock Island before and after World War I. Like all the others, these originally had boiler pressures set to 180 psi (12.4 bar). They were later raised to 200 psi as shown and then to 215 psi (14.8 bar) and the class redesignated K-68B to signify the tractive effort. A further aid to starting a heavy load was the 10,460 lb (4,745 kg) booster added later.

A 14,000-US gallon (52,990 litres) tender added later put 237,600 lb (107,774 kg) on the rails.

Class MP-63l/K-67B (Locobase 7223)

Data from RI to 1951 Diagram Combined Books supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 67239-67245 in April 1927, 67250-67261 in May, and 67262-67263 in June.

Firebox had 82 sq ft (7.62 sq m) of thermic syphons. These were the last Mikados delivered to the Rock Island and differed from the K-64B from Brooks (Locobase 11) only in steam pressure and having two fewer boiler tubes.