The Class 56 is a type of diesel-electric locomotive that was built in the United Kingdom during the 1970s and 1980s. Designed for heavy freight services, these locomotives are known for their robust construction and powerful performance. A total of 135 units were produced, primarily for use by British Rail. Class 56 locomotives are characterized by their distinctive boxy shape and a maximum speed of around 75 mph. They are equipped with a 12-cylinder engine, providing a strong output for hauling large loads. Many units have been preserved and are still in operation today, often seen at heritage railways and special events involving British Rail.