Class H-5A/H-5B (Locobase 14142)

Data from NKP 5-1950 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Lima works numbers were 5428-5437 in March 1917 and Brooks's numbers were 57493-57516 in August 1917.

Lima and Brooks delivered engines in this first, relatively large class of Mikados for the Nickel Plate. As the classification implies, the H-5s of the NKP were essentially duplicates of the New York Central H-5p and -5qs shown in Locobase 1384. All had 14"(356 mm) piston valves. One difference was the Nickel Plate's adoption of one-inch smaller cylinders and their use of Baker valve gear as opposed to the NYC's preference for Walschaert gear.

Like the rest of the railway's motive power, the H-5s served well into the 1950s.

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Class H-6B through H-6F (Locobase 14136)

Data from "2-8-2 Locomotives for the Nickel Plate," Railway Mechanical Engineer, Vol 95, No. 12 (December 1921) , pp. 737-738. Lima works numbers were:

Class number month year

H-6B 6182-6186 December 1920

H-6C 6187 January 1921

H-6D 6307-6316, 6432-6436 October 1922

H-6E 6635-6649 December 1923

H-6E 6650-6664 January 1924

H-6F 6853-6862 June 1924

After Alco-Schenectady delivered ten United State Railroad Administration standard Light Mikado design (Locobase 40) in 1918 (works numbers 59578-59587), Lima picked up the class with the H-6B. These were delivered to the Nickel Plate with the standard boiler layout of 216 small tubes and 40 large tubes. Cylinder dimensions and 14" (356 mm) piston valves were the same as on the original USRA engines. The NKP soon removed three of the tubes.

Many of the engines retained the 27 sq ft (2.51 sq m) of arch tubes originally supplied. Engines 611, 624-625, 627-629, 645, 651, and 665 went through firebox modifications that deleted two of the four arch tubes, leaving 14 sq ft (1.3 sq m) and added 71 sq ft (6.6 sq m) of thermic syphons. With this change, firebox heating surface increased to 341 sq ft (31.7 sq m) or 8.97% of the total evaporative heating surface of 3,802 sq ft (353.3 sq m).

According to the RME report, the USRA's choice for a grate had been a point on which they "commonly have been criticized". The USRA's box grate, said RME, "had a straight horn perpendicular to the grate on the longitudinal center line. With this arrangement when the grates are wide open the maximum distance between the top of one grate and the bottom of the next grate is 4 5/16 in."

Such an opening proved insufficient and Lima used a curved horn "which threw the center of the grate connection pin about 3 1/2 in. ahead of the center. When these grates are wide open there is a maximum of 7 3/8 in. from the top of one grate to the bottom of the next. " RME noted that New York Central Mikados already used the curved-horn design.

Moreover, Lima replaced the drop grates with 10 rocking grates on each side of the firebox. "With the large openings it is possible to dump the fire much more quickly and easily than with the old standard arrangement of drop grates and smaller openings in the rocking grates."

It wouldn't be long before Lima launched its superpower Mikado--the Michigan Central's 8000; see Locobase 9696.

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Class H-6a (USRA) (Locobase 16575)

Data from DeGolyer, Volume 58. Works numbers were 49682-49684 and 49718-49727 in September 1918.

Firebox heating surface area included 27 sq ft (2.51 sq m) in arch tubes and 50 sq ft (4.65 sq m) in the combustion chamber. As with all United States Railroad Administration (USRA) 2-8-2s, piston valve diameter measured 14" (356 mm).

Drury wrote that the NKP only reluctantly accepted the ten engines from the USRA, wincing at the $56,600 price tag. After delivery, however, the road quickly changed its mind. Weighing only 5,000 lb more than the NKP H-5s, they were "good for 6,000 lb more tractive effort", gave the footplate crew mechanical stokers, and larger tenders.

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Class H-6o (USRA) (Locobase 16574)

Data from DeGolyer, Volume 58; and NKP 5-1931 Locomotive Diagrams supplied in August 2022 by Allen Stanley from his extensive Rail Data Exchange collection. See also "Engine No. 587", in the online Encylopedia of Indianapolis at [], and "New Owner for NKP 587, Kentucky Steam Buys Historic Cars", posted 5 March 2021 on the Railfan and Railroad website at [], last accessed 16 September 2023. Works numbers were 49682-49684 and 49718-49727 in September 1918.

Firebox heating surface area included 27 sq ft (2.51 sq m) in arch tubes and 50 sq ft (4.65 sq m) in the combustion chamber. As with all United States Railroad Administration (USRA) 2-8-2s, piston valve diameter measured 14" (356 mm).

Most of the class was sold for scrap in 1944-1946. For some reason the 599 remained on the roster until August 1953.

587, the final survivor, wound up in Indianapolis as a donation in September 1955. It ran in excursion service after its first restoration between 1988 and 2003. Stored at Indiana Transportation Museuam, then at Noblesville, Ind until it was