2-8-2
In the Whyte notation, a 2-8-2 is a railroad steam locomotive that has one unpowered leading axle followed by four powered driving axles and one unpowered trailing axle. This configuration of steam locomotive is most often referred to as a Mikado (frequently shortened to Mike), but it is also referred to as a MacArthur. The 2-8-2 was particularly popular in North America, but was also used in continental Europe and elsewhere.
The equivalent UIC classification is 1'D1'.
The 2-8-2 arrangement allows the locomotive's firebox to be placed behind, instead of above, the driving wheels, allowing a large 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 possible when they did not impinge on the firebox, this meant that the 2-8-2 was capable of higher speeds with a heavy train than a 2-8-0.
History
The class name Mikado originates from a group of 2-8-2 locomotives that were constructed in 1897 for the Nippon Railway of Japan. In 1885, the Gilbert & Sullivan opera The Mikado premiered, so the name was on the minds of many in America.
The 2-8-2 was one of the more common configurations in the first half of the 20th century before dieselization. Nearly 2,200 of this type were constructed by ALCO, Lima and Baldwin based on designs of the USRA between 1917 and 1944. Of all of the USRA designs, the Mikado proved to be the most popular.
Mikado remained the class name until the Attack on Pearl Harbor in 1941. Seeking a more "American" name, MacArthur came into use to describe the locomotive type; this name is based on General Douglas MacArthur. Since the war, the class name Mikado has again become the most common name for this locomotive type.
Geographical distribution
United States
The 2-8-2 saw great success in the United States, mostly as a freight locomotive. It largely replaced the 2-8-0 "Consolidation" type as the heavy freight locomotive type in the second decade of the 20th century. Tractive effort was similar to the best 2-8-0s, but a developing requirement for higher speed freight trains drove the shift to the 2-8-2. The type was in turn pushed from the top-flight trains by larger freight locomotive arrangements such as 2-10-2, 2-8-4, 2-10-4 and articulated locomotives, but no successor type became ubiquitous and the "Mike" remained the most common road freight locomotive with most railroads until the end of steam. In excess of 11,000 of this type were built for North American service, which comprised approximately one-fifth of all locomotives in service at the time.
Almost all North American railroads rostered the type; notable exceptions included the Boston and Maine Railroad, the Delaware and Hudson Railway, and the Norfolk and Western Railway. The largest users included the New York Central Railroad (715 examples), Baltimore and Ohio Railroad (610), Pennsylvania Railroad (579), Illinois Central Railroad (565), Milwaukee Road (500), and the Southern Railway (435).
United Kingdom
The 2-8-2 type saw little success on British rails, probably because of short, antiquated British freight trains which did not require such power. Sir Nigel Gresley of the London and North Eastern Railway designed two Mikado types of note; the P1 was a freight derivative of his famed A1 4-6-2s, inspired by the Pennsylvania Railroad's twin K4s 4-6-2s and L1s 2-8-2s. Two were built, but there was never really much call for their ability and they remained underutilised throughout their short existence.
Gresley's other class of Mikados was his P2 class. These were express passenger locomotives rather more inspired by European influences than American. They were built to haul heavy expresses north of Edinburgh in hilly terrain, where Gresley thought the extra tractive effort possible with a 2-8-2 might serve well. Unfortunately, poor self-centering on the leading truck meant that the lead driving wheels wore against the rails on tighter curves, being hard on both track and wheels. Gresley's successor Edward Thompson converted the P2s into (rather unattractive, by most opinions) Pacifics.
The Great Western Railway operated a class of 54 2-8-2 tank engines designed by C. B. Collett. As early as 1906 their then chief mechanical engineer, G. J. Churchward, planned a class of 2-8-2 tank engines to handle heavy coal trains in South Wales. However the plan was abandoned as it was feared they would be unable to handle the sharp bends found on Welsh mineral branches. Instead, Churchward designed the 4200 Class of 2-8-0 tank engines, of which nearly 200 were built. In the 1930s, coal traffic declined, and many of these engines stood idle; they could not be switched to other duties because of their limited operating range. Collett, as Churchward's successor, decided to rebuild some of the 4200 Class engines as 2-8-2s. The addition of a trailing axle increased the engines' operating ranges by allowing more coal and water storage. In all 54 engines were modified in this way. The 7200 Class tank engines as they were known remained in service until the end of steam in Britain in the early 1960s.
Germany
German 2-8-2s were built in both passenger and freight types. The passenger locomotives were used mainly in mountainous terrain (BR 39). Although eclipsed by the success of German 2-10-0 designs, many successful 2-8-2 freight locomotives were also built, all of type BR 41. The third type of German 2-8-2 locomotive was the tank locomotive (BR 86, BR 93).
Austria
The 4-cylinder compound class 470, developed in 1914 by Karl Gölsdorf, was built for express trains on mountain lines. From 1927 some the locomotives were rebuilt to 2-cylinder overheated steam locomotives class 670. Numbered class 39 from 1938 on, they remained in service until 1957.
France
France built a fairly large number of 2-8-2s, both tender-hauling and tank locomotives. The most powerful French Mikado was the 141 P, at 3,000 hp.
See also
- USATC S200 Class - a class of 2-8-2 that was built by American manufacturers for use in Europe during World War II
- USATC S118 Class
External links
- USRA Mikados
- 2-8-2 or Mikado (Trains Magazine)