Located on 129 acres, the Museum is approximately 16 miles southwest of downtown St. Louis, on a site which includes one of the two first man-made railroad tunnels west of the Mississippi River. The Museum site features more than four miles of switching and exhibition track. Additionally, the Museum houses a nationally acclaimed research library of transportation-related memorabilia and documents. With over 70 locomotives, half of them “one-of-a-kind” or “sole survivors” of their type, the Museum has one of the most complete collections of American railroad motive power. Collections include automobiles, buses, streetcars, aircraft, horse-drawn vehicles, and riverboat materials that are constantly expanding to reflect the ever-changing nature of transportation.