4-4-2+2-4-4
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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.
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.[1]
| Gauge | Railway | Class | Works no. | Units | Year | Builder |
|---|---|---|---|---|---|---|
| 3 ft 6 in | Tasmanian Government Railways | M | 5523–5524 | 2 | 1912 | Beyer, Peacock |
| 4 ft 8+1⁄2 in | Entre Rios Railway (FCER), Argentina | 6360–6364 | 5 | 1927 | Beyer, Peacock | |
| 4 ft 8+1⁄2 in | Argentine North Eastern (FCNAR) | 6645–6647 | 3 | 1930 | Beyer, Peacock |
Usage
Argentina
Eight locomotives were built for Argentina to run on 4 ft 8+1⁄2 in (1,435 mm) standard gauge.[1]
- Five were built for the Entre Ríos Railway (Ferrocarril Entre Ríos, FCER) in 1927.[1]
- Another three were built for the Argentine North Eastern Railway (Ferrocarril Nordeste Argentino, FCNAR) in 1930.[1]
After nationalization in 1948, all these locomotives were rostered on the Ferrocarril General Urquiza (FCGU).[1]
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.[1][2]
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 They were difficult to maintain and, despite their haulage abilities and speed, both were withdrawn from service some time after the arrival of the R class 4-6-2 Pacific types in 1924.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.[2]
References
