The British Railways Class 56 is a heavy freight diesel locomotive introduced in the late 1970s to replace ageing Type 2 and Type 4 fleets. Designed for high tractive effort, it featured a powerful Ruston-Paxman engine and Co-Co wheel arrangement. Early production involved Romanian-built locomotives, which suffered reliability problems, prompting later construction in Britain by Brush Traction with improved quality. The Grids became mainstays of coal, steel, and aggregate traffic across England and Wales. Though withdrawn from most mainline duties by the 2000s, several examples were preserved, while others found second lives with private freight operators, and can still be found working hard today.