Under the Whyte notation for the classification of steam locomotives, represents the wheel arrangement of two leading wheels on one axle, usually in a leading truck, eight powered and coupled driving wheels on four axles and two trailing wheels on one axle, usually in a trailing truck. This configuration of steam locomotive is most often referred to as a Mikado, frequently shortened to Mike.
It was also at times referred to on some railroads in the United States as the McAdoo Mikado and, during World War II, the MacArthur.
The notation 2-8-2T indicates a tank locomotive of this wheel arrangement, the "T" suffix indicating a locomotive on which the water is carried in tanks mounted on the engine rather than in an attached tender.
Overview
The 2-8-2 wheel arrangement allowed the locomotive's firebox to be placed behind instead of above the driving wheels, thereby allowing a larger firebox that could be both wide and deep. This supported a greater rate of combustion and thus a greater capacity for steam generation, allowing for more power at higher speeds. Allied with the larger driving wheel diameter which was possible when they did not impinge on the firebox, it meant that the 2-8-2 was capable of higher speeds than a with a heavy train. These locomotives did not suffer from the imbalance of reciprocating parts as much as did the 2-6-2 or the , because the center of gravity was between the second and third drivers instead of above the centre driver.
The first 2-8-2 locomotive was built in 1884. It was originally named Calumet by Angus Sinclair, in reference to the engines built for the Chicago & Calumet Terminal Railway (C&CT). However, this name did not take hold.
The wheel arrangement name "Mikado" originated from a group of Japanese type 9700 2-8-2 locomotives that were built by Baldwin Locomotive Works for the gauge Nippon Railway of Japan in 1897. In the 19th century, the Emperor of Japan was often referred to as "the Mikado" in English. The Gilbert and Sullivan opera, The Mikado, set in Japan, had premiered in 1885 and achieved great popularity in both Britain and America.
The 2-8-2 was one of the more common configurations in the first half of the 20th century, before dieselisation. Between 1917 and 1944, nearly 2,200 of this type were constructed by Baldwin, the American Locomotive Company (ALCO) and the Lima Locomotive Works, based on designs by the United States Railroad Administration (USRA). It was also known as the "McAdoo Mikado" in the United States, after William Gibbs McAdoo who was appointed as Director General of Railroads when the United States commenced hostilities during the latter part of the First World War and the USRA was established. Of all of the USRA designs, the Mikado proved to be the most popular. The total American production was about 14,000, of which 9,500 were for local customers and the rest exported.
"Mikado" remained the type name until the attack on Pearl Harbor in 1941. Seeking a more American name, "MacArthur", after General Douglas MacArthur, came into use to describe the locomotive type in the United States. After the war, the type name "Mikado" again became the most common for that locomotive type.
Usage
Locomotives of this wheel arrangement saw service on all six populated continents. The 2-8-2 type was particularly popular in North America, but was also used extensively in Continental Europe and elsewhere.
Argentina
broad gauge
The Buenos Aires and Pacific Railway bought eighteen 2-8-2T locomotives in three batches of six as their class 701 class. The first two batches came from North British Locomotive Company in 1908 and 1912, the third from Henschel & Son in 1913.
The BA&P also bought eight 2-8-2 tender locomotives from Beyer, Peacock & Company in 1928 as their 3001 class.
The Central Argentine Railway (FCCA) bought fifteen 2-8-2T locomotives as their class C7 in 1912; they were built by Robert Stephenson & Company with works numbers 3506 to 3520.
The FCCA also bought sixty 2-8-2 locomotives: twenty class CS8A from Beyer, Peacock & Company in 1926, and another twenty in 1928 from Robert Stephenson & Company. The final twenty to class CS9A were supplied by Vulcan Foundry in 1930. Both classes were cross-compound locomotives with one high-pressure cylinder with a bore of and one low-pressure cylinder with a bore of , with a stroke of . The earlier class had coupled wheels with a diameter of , whereas on the later class they were .