The San Luis and Rio Grande Railroad (SLRG) began operations in 2003, running on 154 miles of former Denver and Rio Grande Western Railroad line in Colorado. Originally the line was part of RailAmerica but was purchased by Permian Basin Railways in 2005 and is now operated as a subsidiary.

The railroad operates three lines radiating from Alamosa, Colorado: east to La Veta (over La Veta Pass) where it connects with the Union Pacific Railroad, south to Antonito where it connects with the Cumbres and Toltec Scenic Railroad, and west to South Fork.

It operates a tourist train called the Rio Grande Scenic Railroad to La Veta and Antonito during the summer months. According to the Rio Grande Scenic Railroad's website, "The Rio Grande Scenic Railroad is a collaboration of the San Luis and Rio Grande Railroad, which owns and operates the freight railroad, the Denver and Rio Grande Historical Foundation which is committed to preserving the railroad history of the San Luis Valley, and the Alamosa and La Veta Chambers of Commerce."