UIC class 2B1+1B2 Turkish class 25+25 First use 1912 | French class 221+122 Russian class 2-2-1+1-2-2 | |
Swiss class 2/5+2/5, 4/10 from the 1920s | ||
Under the Whyte notation for the classification of steam locomotives by wheel arrangement, a 4-4-2+2-4-4 is a Garratt articulated locomotive. The wheel arrangement is effectively two 4-4-2 locomotives operating back to back, with each power unit having four leading wheels on two axles in a leading bogie, four powered and coupled driving wheels on two axles, and two trailing wheels on one axle in a trailing truck. Since the 4-4-2 type is usually known as an Atlantic, the corresponding Garratt type is often referred to as a Double Atlantic.
Contents
Overview
The 4-4-2+2-4-4 was not a common Garratt wheel arrangement. Only ten were built, all by Beyer, Peacock and Company, the owner of the Garratt patent.
Argentina
Eight locomotives were built for Argentina to run on 4 ft 8 1⁄2 in (1,435 mm) standard gauge.
After nationalization in 1948, all these locomotives were rostered on the Ferrocarril General Urquiza (FCGU).
Australia
The first Garratt locomotives to be built to the 4-4-2+2-4-4 wheel arrangement were a pair of M class passenger locomotives for the 3 ft 6 in (1,067 mm) gauge Tasmanian Government Railways in Australia in 1912. They were acquired to haul express passenger trains between Launceston and Hobart.
The two M class engines were the only eight-cylinder Garratt locomotives in the world. They were difficult to maintain and, despite their haulage abilities and speed, both were withdrawn from service some time after the arrival of the R class 4-6-2 Pacific types in 1924. Both locomotives were scrapped and cut up in the late 1940s.