The London and North Western Railway (LNWR) Class G were several related classes of 0-8-0 steam locomotives.
These 0-8-0s were the principal work-horses for freight traffic on the latter-day London & North Western.
The outside high-pressure cylinders were removed and the inside low-pressure cylinders were re-used, in their original position, to make a two-cylinder simple expansion engine.
The rebuilt engines were easily distinguished from the new builds by having "piano fronts".
The remaining 91 engines were inherited by the LMS in 1923.