2-4-2+2-4-2

In the Whyte notation for the classification of steam locomotives by wheel arrangement, the 2-4-2+2-4-2 is a Garratt articulated locomotive. The wheel arrangement is effectively two 2-4-2 locomotives operating back to back, with the boiler and cab suspended between the two power units. Each power unit has a single pair of leading wheels in a leading truck, followed by two coupled pairs of driving wheels, with a single pair of trailing wheels in a trailing truck. Since the 2-4-2 type is sometimes known as a Columbia, the corresponding Garratt type could be referred to as a Double Columbia.

Other equivalent classifications are:

• UIC classification: 1B1+1B1 (also known as German and Italian classifications)
• French classification: 121+121
• Turkish classification: 24+24
• Swiss classification: 2/4+2/4 up to the early 1920s, later 4/8

Overview

This was the rarest of all Garratt types, with only four constructed to this wheel arrangement. All of them were built in 1943 by Beyer, Peacock for the 1,000 mm (3 ft 3 ³⁄₈ in) metre gauge Leopoldina Railway in Brazil. They were allocated engine numbers 400 to 403 on that system.^[1]

References

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