The Tracy Subdivision or Tracy Sub is a railway line in southern Minnesota owned and operated by the Dakota, Minnesota and Eastern Railroad (DM&E) subsidiary of Canadian Pacific. It begins at the end of the Waseca Subdivision in Waseca, Minnesota in the east and runs approximately 124 miles (200 km) west to Tracy where the rails continue as the Huron Subdivision. U.S. Highway 14 closely follows the train route.
The rail line had been built westward from Winona, reaching Waseca in 1868. The Chicago and North Western Railway had taken ownership of the Winona and St. Peter Railroad the previous year, and continued building the line west, though the Winona and St. Peter continued to operate under the old name for a considerable time afterward. The rails extended to Mankato and St. Peter in 1870, then New Ulm in 1871, and reached into Dakota Territory (now South Dakota) in 1872. The first branch line was completed in 1878 from Sleepy Eye to Redwood Falls, Minnesota. West of Tracy, the original mainline had gone northwest to Watertown, South Dakota and nearby Lake Kampeska, so a new line was started from Tracy in 1879 and reached Pierre two years later.
Passenger train service continued on the line from its formation until the 1950s when the Dakota 400 was shortened to only run as far as Mankato. The train was renamed the Rochester 400, but passenger service ended entirely on July 23, 1963 when the Rochester 400 made its final run. Chicago and North Western continued to operate the line across southern Minnesota and South Dakota until the 1980s, but started planning to abandon it. The Dakota, Minnesota and Eastern Railroad was formed and took over the line in 1986. Canadian Pacific moved to purchase DM&E in 2007, which was completed in 2008.