The EMD SW1 is a type of diesel-electric switcher locomotive built by Electro-Motive Division (EMD) from 1939 to 1953. It features a 600-horsepower engine and is designed for switching duties in rail yards, moving freight cars short distances. The SW1 is known for its compact size and reliability, making it a popular choice for many railroads. With a total production of around 1,200 units, the EMD SW1 has been used by various railroads across the United States and beyond. Its simple design and robust performance have allowed many units to remain in service or be preserved by enthusiasts and museums, showcasing its lasting impact on railroading.