4-4-2+2-4-4

4-4-2+2-4-4 (Double Atlantic)

Equivalent classifications
UIC class	2B1+1B2
French class	221+122
Turkish class	25+25
Swiss class	2/5+2/5, 4/10 from the 1920s
Russian class	2-2-1+1-2-2

First known tank engine version
First use	1912
Country	Australia
Locomotive	TGM M class
Railway	Tasmanian Government Railways
Designer	Beyer, Peacock & Company
Builder	Beyer, Peacock & Company

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.

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Overview

The 4-4-2+2-4-4 was not a common Garratt wheel arrangement. Only ten were built, all by Beyer, Peacock & Company, the owner of the Garratt patent.^[1]

**4-4-2+2-4-4 Garratt production list – All manufacturers**^[1]
Gauge	Railway	Class	Works no.	Units	Year	Builder
3 ft 6 in	Tasmanian Government Railways	M	5523–5524	2	1912	Beyer, Peacock & Company
4 ft 8+1⁄2 in	Entre Ríos Railway, Argentina		6360–6364	5	1927	Beyer, Peacock & Company
4 ft 8+1⁄2 in	Argentine North Eastern Railway		6645–6647	3	1930	Beyer, Peacock & Company

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 in 1927.^[1]
Another three were built for the Argentine North Eastern Railway in 1930.^[1]

After nationalization in 1948, all these locomotives were rostered on the General Urquiza Railway.^[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 They were difficult to maintain and, despite their haulage abilities and speed, both were withdrawn from service some time after the arrival of the R class in 1924 and scrapped in the late 1940s.^[2]

References

^ ^a ^b ^c ^d ^e ^f ^g Hamilton, Gavin N., The Garratt Locomotive - Garratt Locomotives produced by Beyer, Peacock, retrieved 10 November 2012
^ ^a ^b A Brief History of the Garratt Locomotive in Australia Australian Railway Historical Society Bulletin issue 185 March 1953 page 25

External links

Media related to 4-4-2+2-4-4 locomotives at Wikimedia Commons

v t e Steam locomotive wheel arrangements (Whyte notation)
Single engine types	0-2-2 0-2-4 2-2-0 2-2-2 2-2-4 4-2-0 4-2-2 4-2-4 6-2-0 0-3-0 (monorail) 0-4-0 0-4-0+4 0-4-2 0-4-4 0-4-6 2-4-0 2-4-2 2-4-4 2-4-6 4-4-0 4-4-2 4-4-4 4-4-6 0-6-0 0-6-2 0-6-4 0-6-6 2-6-0 2-6-2 2-6-4 2-6-6 4-6-0 4-6-2 4-6-4 0-8-0 0-8-2 0-8-4 0-8-6 2-8-0 2-8-2 2-8-4 2-8-6 4-8-0 4-8-2 4-8-4 4-8-6 6-8-6 0-10-0 0-10-2 2-10-0 2-10-2 2-10-4 4-10-0 4-10-2 0-12-0 2-12-0 2-12-2 2-12-4 4-12-2 4-14-4
Divided drive and Duplex engine types	0-2-2-0 2-2-2-0 2-2-2-2 2-2-4-0 4-2-2-0 2-4-6-2 4-4-4-4 6-4-4-6 4-4-6-4 4-6-4-4
Articulated locomotives Fairlie, Meyer and Garratt types	0-4-0+0-4-0 2-4-0+0-4-2 2-4-2+2-4-2 4-4-2+2-4-4 0-6-0+0-6-0 0-6-2+2-6-0 2-6-0+0-6-2 2-6-2+2-6-2 4-6-0+0-6-4 4-6-2+2-6-4 4-6-4+4-6-4 2-8-0+0-8-2 2-8-2+2-8-2 4-8-0+0-8-4 4-8-2+2-8-4 4-8-4+4-8-4
Articulated locomotives Mallet types	0-4-4-0 0-4-4-2 2-4-4-0 2-4-4-2 0-6-6-0 2-6-6-0 2-6-6-2 2-6-6-4 2-6-6-6 2-6-8-0 4-4-6-2 4-6-6-2 4-6-6-4 0-8-6-0 0-8-8-0 2-8-8-0 2-8-8-2 2-8-8-4 4-8-8-2 4-8-8-4 2-10-10-2
Articulated locomotives Triplex and other Multiplex types	2-8-8-8-2 2-8-8-8-4 2-8-8-8-8-2 0-6-2+2-4-2-4-2+2-6-0 2-6-6-2+2-6-6-2 2-8-8-8-8-8-2 2-10-10-10-10-10-2 2-4-4-2+2-8-8-2+2-4-4-2
Articulated locomotives Engerth types	0-4-4 0-4-6 2-6-2 0-6-4 0-6-4-0 0-8-4 0-8-6
Geared locomotives	Shay Climax Heisler Willamette
Other notation forms: AAR Swiss UIC

This page was last edited on 25 May 2022, at 02:00

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