
A 2-6-2+2-6-2 South African Garratt
A Garratt locomotive is a type of steam locomotive that is articulated into three parts. Its boiler is mounted on the centre frame, and two steam engine units are mounted on separate frames, one on each end of the boiler.
Articulation permits larger locomotives to negotiate curves and lighter rails that might restrict large rigid-framed locomotives. Garratt locomotives effectively doubled the power of the largest conventional locomotives operating on a railway, thus reducing the need for multiple locomotives and crews.