The Class 57 is a type of diesel locomotive used primarily in the United Kingdom. Built by Brush Traction in the late 1990s, these locomotives were originally refurbished from older British Rail Class 56 models. They are known for their reliability and versatility, often used for both passenger and freight services. Class 57 locomotives are equipped with a Cummins engine and feature a distinctive blue and yellow livery. They are commonly operated by various rail companies, including Freightliner and West Midlands Trains, and have become a familiar sight on British railways, contributing to the efficiency of rail transport.