2-4-2+2-4-2

UIC class1B1+1B1, 1’B1’+1’B1’

UIC class1B1+1B1, 1’B1’+1’B1’

French class121+121

Turkish class24+24

2-4-2+2-4-2

Equivalent classifications UIC class 1B1+1B1, 1’B1’+1’B1’ French class 121+121 Turkish class 24+24 Swiss class 2/4+2/4, 4/8 from the 1920s Russian class 1-2-1+1-2-1

First known tank engine version First use 1943 Country Brazil Railway Leopoldina Railway Designer Beyer, Peacock and Company Builder Beyer, Peacock and Company Evolved from 2-4-0+0-4-2

Under the Whyte notation for the classification of steam locomotives by wheel arrangement, the 2-4-2+2-4-2 is a Garratt 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.

This was the rarest of all Garratt types, with only one class of four locomotives constructed to this wheel arrangement.^[1] It most likely evolved from the 2-4-0+0-4-2 Double Porter Garratt, with the trailing wheels added on each engine unit to improve stability at speed.