Geared steam locomotive
A geared steam locomotive is a type of steam locomotive which uses gearing, usually reduction gearing, in the drivetrain, as opposed to the common directly driven design.
Queensland Beyer-Garratt class
A Garratt (also known as Beyer-Garratt) is a type of steam locomotive that is articulated in three parts. Its boiler is mounted on the centre frame, and two steam engines 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. Many Garratt designs aimed to double the power of the largest conventional locomotives operating on their railways, thus reducing the need for multiple locomotives and crews.