B&O's Cumberland viaduct was built as a brick arch structure during the years 1849-1851. The B&O main out of Cumberland passed south through the "deep cut". The deep cut provides the West End of the B&O with access to the Potomac River Valley, towards Keyser, and Grafton. The viaduct passes over city streets, Will's Creek, and the Western Maryland tracks (now used by the Western Maryland Scenic Railroad). The viaduct is double-tracked, as is the deep cut. The southern end of the cut is wide enough for triple track. The C&P's Potomac Wharf Branch tracks once shared the deep cut right of way. The Viaduct has 14 of the 50 foot brick arches on stone pillars. It is a total of 850 feet long. It was reinforced with concrete in 1909.At Viaduct Jct., heading west, the line bifurcates to the Keystone Division to the right (to Chicago via Pittsburgh), and the Mountain subdivision on the left (Grafton and points west in Ohio). The Viaduct Junction Tower ("ND") was removed by CSX in 1997, and the junction was controlled by CSXT's Jacksonville, Florida office.

Here's a CSX southbound over the Viaduct, as the 2nd track is removed.