Grand Rapids & Indiana / Pennsylvania 2-8-2 "Mikado" Locomotives in the USA

Class L-2s (Locobase 16582)

Data from tables in 1930 Locomotive Cyclopedia and from American Locomotive Company, Standardized Locomotives, US Railroad Administration (Alco Pamphlet 10049, 1918), pp. 16-17, reprinted by (Ocean, NJ: Specialty Press , 1973) and DeGolyer, Volume 58, pp. 61+. (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 .)

Having invested its own resources in buying and building 574 L-1s (Locobase 32), the Pennsylvania System wasn't interested in the USRA's very similar light Mikado (Locobase 40) and refused an allocation of 33 engines in 1919. But PRR Lines West constituent GR&I took this quintet.

Although they eventually landed in the PRR's numbering system, the class remained on GR&I metals until their scrapping in 1949-1953.

Class L1s (Locobase 32)

Data confirmed by table in May 1916 issue of Railway Mechanical Engineer. See also DeGolyer, Volume 51, pp. 171+; Issue 28, Locomotive testing plant at Altoona, Pa: Bulletin, 1914; " New Locos, Pennsylvania Railroad," Locomotive Magazine, Volume XX [20] (14 November 1914), pp. 284-287; and "Pacific and Mikado Type Locomotives, Pennsylvania R R", Railway Review, Volume 55, No 1 (4 July 1914), pp. 4-8; and John W Orr, Set Up Running : the Life of a Pennsylvania Railroad Engineman, 1904-1949 (Pennsylvania State University Press, 2001), p. 125 and DeGolyer, Volume 59, pp. 275+. (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 .)

Another one of the Pennsy's classes built in heroic numbers over five years; among all American 2-8-2s only the US Railroad Administration's Light Mikados (Locobase 40) were built in greater numbers to a single design for a non-Governmental railroad.

These Mikes used the same Belpaire boiler design as did the famous K-4s Pacifics (Locobase 159) and the class gave the same long service. Perhaps surprisingly, the piston valves had a relatively modest 12" (305 mm) diameter. Firebox heating surface area included the 62 sq ft (5.75 sq m) in the combustion chamber and 34.6 sq ft (3.2 sq m) of arch tubes.

The test bulletin acknowledged that the tubes were relatively short, but reported that the length was a "direct result of trials in which it developed that free steaming can be secured only by a tube of moderate length and one having a certain ratio of length to diameter." And the L1s delivered a nearly ideal tube length-to-diameter ratio of 101:1.

Juniata produced the lion's share -- 344 -- with Baldwin adding 205, and Lima 25. Most went to Lines East with only 50 serving west of the Appalachians.

John Orr's father quoted a long-time engineer--O.P.-- as claiming in the mid-1920s "the best all-purpose locomotive that had been developed thus far [on the Pennsy] was the L1s. It could run fast, steam easily, ride well, and, despite its rather large size for a Mikado, it was economical to operate."

On the railroad forum rec.models.railroad -- []

Mark Newton provided an excellent outline of the difference between a Pennsy Belpaire and others:

"The Pennsy and the railroad trade journals of the time alike described the PRR designs as a modified Belpaire type. In this case the wrapper and sidesheets were typically separate, with the seam below the radius of the wrapper plate, which is larger by comparison with other Belpaire designs. Both wrapper and crown sheet have a large radius set, as

opposed to being nearly flat. The layout of the crown stays is slightly radial, as opposed to the parallel layout of a more typical Belpaire firebox. The combustion chamber was relatively lengthy, and projected well forward of the firebox sidesheets."

[Date: Thurs, Aug 21 2003 9:59 am - Email: Mark Newton marknew ...@optusnet.com.au>

Groups: rec.models.railroad]

Locobase offers the opinion that the integration of the combustion chamber into the top line of the boiler helped these engines achieve a distinctive and more elegant look (in a rivets-and-steel-plate techno art sort of way) that reached its apotheosis in the M-1 Mountains (see Locobase 220).