2-4-0+0-4-2
Under the Whyte notation for the classification of steam locomotives by wheel arrangement, is an articulated locomotive, usually of the Garratt type. The wheel arrangement is effectively two locomotives operating back to back, with the boiler and cab suspended between the two power units. Each power unit has two leading wheels on one axle, four powered and coupled driving wheels on two axles and no trailing wheels. A similar wheel arrangement exists for Mallet locomotives, but is referred to as 2-4-4-2 since only the front engine unit can pivot.
History
This was the second rarest Garratt wheel arrangement. Only five locomotives were constructed to this arrangement, four of which were built by Beyer, Peacock and Company.The four BP locomotives comprised three for the São Paulo Railway of Brazil in 1915, and one for the gauge Ceylon Government Railway in 1929, the CGR's class H1.
One more was built in 1919 by the São Paulo Railway, for its own use on.