Manchester South Junction and Altrincham Railway Viaduct

The Manchester South Junction and Altrincham Railway Viaduct is a substantial structure built in the 19th century, approximately 2 ¾ miles (1.75 miles) long, running from Manchester Piccadilly Station via Oxford Road and Deansgate. It follows the general course of the River Medlock, crossing it at several points, and splits into two branches at Castlefield.

The viaduct is primarily constructed of brick and incorporates 224 arches, most averaging around 30 feet in span and height, with a width of 28 feet. Many arches, particularly near Manchester Oxford Road and Deansgate stations, have been in-filled and converted into commercial premises. The ground level is lower between Manchester Piccadilly and Oxford Road stations, resulting in taller arches in this section. A brick parapet has been altered and rebuilt in places, and some arches have undergone later repairs.

The viaduct includes a series of predominantly arched, cast-iron bridges designed by Edward Taylor Bellhouse, William Baker, and William Cubitt, spanning streets, the Rochdale Canal, and the Bridgewater Canal. These bridges generally have a span of 70 feet, although one by William Baker spanning the Rochdale Canal measures 105 feet. The bridges showcase varying architectural styles; some feature highly decorative Gothic-style ironwork and detailing, including castellated towers referencing the Roman fort at Castlefield, while others, such as the bridge over Gloucester Street, have a more classical design. A bridge over Egerton Street, originally by William Baker, was replaced with steel in 1976. The brick Irwell Bridge at the north-west end features two segmental arches, each with a span of approximately 65 feet, a central pier, and cut-waters. It showcases rusticated stone voussoirs and pilaster strips to the central pier and abutments, with cast-iron panelling in the parapet above the western arch.

Later 20th and early 21st century gantries have been added along the viaduct's length following electrification of the line. Various buildings are also attached to or abutting the viaduct, but these are later in date and unrelated to the viaduct's original purpose, and are excluded from the listing. Manchester Piccadilly Station, Deansgate Station, and Manchester Oxford Road Station, which are built on and alongside the viaduct, are separately listed at Grade II.