Railroads have played an important role in South Dakota transportation since the mid-19th century. Some of railroad track were built in South Dakota during the late 19th century and early 20th century, but only are active. BNSF Railway is the largest railroad in South Dakota; the Rapid City, Pierre and Eastern Railroad (formerly the Dakota, Minnesota and Eastern) is the state's other major carrier. Other state carriers include Dakota Southern Railway, Dakota and Iowa Railroad, Ellis and Eastern Railroad, Sunflour Railroad, Canadian Pacific Railway, and the Sisseton Milbank Railroad. Rail transportation in the state is mostly freight, but there are two passenger heritage railroads: the Black Hills Central and the Prairie Village, Herman, and Milwaukee. However, South Dakota is one of the two contiguous states that lack Amtrak service. (South Dakota is the only contiguous state that "never had" Amtrak—Wyoming used to be served by the San Francisco Zephyr and the Pioneer.)