The Moffat Tunnel is a 6.2-mile (10 km) rail tunnel located in the Rocky Mountains of Colorado. It connects the towns of East Portal and West Portal, allowing trains to pass through the mountains without having to navigate steep grades. The tunnel was completed in 1927 and is named after the railroad executive David Moffat, who envisioned the project. The tunnel serves as a vital transportation link for the Denver and Rio Grande Western Railroad and is used primarily for freight trains. It significantly reduces travel time and improves efficiency by providing a direct route through the challenging mountain terrain.