Classic Streamliners - TRAINCYCLOPEDIA
2-6-2 "Prairie" Steam Locomotive
Under the Whyte notation for the classification of steam locomotives, 2-6-2 represents the wheel arrangement of two leading wheels, six coupled driving wheels and two trailing wheels. This arrangement is commonly called a Prairie.
The majority of American 2-6-2s were tender locomotives, but in Europe tank locomotives, described as 2-6-2T, were more common. The first 2-6-2 tender locomotives for a North American customer were built by Brooks Locomotive Works in 1900 for the Chicago, Burlington and Quincy Railroad, for use on the Midwestern prairies. The type was thus nicknamed the Prairie in North American practice. This name was often also used for British locomotives with this wheel arrangement.
As with the 2-10-2, the major problem with the 2-6-2 is that these engines have a symmetrical wheel layout, wherein the center of gravity is almost over the center driving wheel. The reciprocation rods, when working near the center of gravity, induce severe side-to-side nosing which results in severe instability if unrestrained either by a long wheelbase or by the leading and trailing trucks. Though some engines, like the Chicago and Great Western of 1903, had the connecting rod aligned onto the third driver, most examples were powered via the second driver and were prone to the nosing problem.
The 2 ft (610 mm) gauge Sandy River and Rangeley Lakes Railroad in Franklin County, Maine, was a major narrow gauge 2-6-2 user.
In the United States, the type evolved from the 2-6-0 configuration. The Atchison, Topeka and Santa Fe Railway (AT&SF) became a pioneer of the type in the United States in 1901 and one of the largest fleet users of the type. Problems the road encountered with the type included steam leakage in the compound cylinder plumbing and instability at speed. The former problem was solved by converting them to simplex two-cylinder locomotives; the latter problem required new Pacific types with four-wheeled guide trucks. The Prairie types were rebuilt with smaller drivers for slightly slower fast freight service. These engines tended to enjoy very long service lives, and outlasted many a newer, more efficient steam locomotive on the Santa Fe and elsewhere. This was due to their modest weight, good speed and ability to operate well in reverse, which made them valuable for branch line operations.
In 1902, the AT&SF had a 2-6-2 with a high, at the time, boiler pressure of 220 pounds per square inch (1,517 kilopascals), mounted on a large 41 square feet (3.8 square meters) fire grate.
More than a thousand examples of the 2-6-2 wheel arrangement existed in the United States. Of these, one hundred were high-wheeled engines with larger than 69 inches (1,753 millimeters) drivers. The Lake Shore & Michigan Southern operated locomotives with 80 inches (2,032 millimeters) drivers, but this did not overcome their inherent instability. They were never as successful in passenger service in the U.S. as they were in other nations.
2-6-2 Prairie Overview
UIC class: 1C1
French class: 131
Turkish class: 35
Swiss class: 3/5
Russian class: 1-3-1
First known tank engine version
First use: 1875
Country: Cape of Good Hope
Locomotive: CGR 2nd Class 2-6-2TT
Railway: Cape Government Railways
Designer: Robert Stephenson and Company
Builder: Robert Stephenson and Company
First known tender engine version
First use: 1900
Country: United States of America
Railroad: Chicago, Burlington and Quincy Railroad
Builder: Brooks Locomotive Works
Evolved from: 2-6-0
Drawbacks: Nosing at speed
Diagram of the 2-6-2 Wheel Arrangement: one small leading wheel, three large driving wheels joined together with a coupling rod, and one small trailing wheel.
Logs being transported by a 2-6-2 of the Comox & Campbell Lake Tramway Co., Vancouver Island, BC, ca. 1925.
By Musée McCord Museum, via Wikimedia Commons
A 2-6-2 Prairie Slideshow.
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Text: wikipedia.org. Images: Public Domain; http://www.commons.wikimedia.org (unless otherwise specified) and 17 U.S. Code § 107 fair use. References: Lewis, Robert G. The Handbook of American Railroads. New York: Simmons-Boardman Publishing Corporation, 1951, 2nd Edition 1956. Site Map Contact webmaster HERE.