The bridge spanned the Irwell just before the terminus at Liverpool Road and was not part of the original plan.

The route was extended into Manchester necessitating a bridge over the River Irwell to a station at the west end of Liverpool Road.

The bridge carries a twin standard gauge track layout and a 5.5-metre (18 ft) wide roadway.

[2] The bridge is built of sandstone with rusticated ashlar facings and radiating stonework that frames the arches and forms the spandrel panels.

Horizontal stone courses make up the parapet and the pilasters of the central cutwater and span ends, and the coping and cornices are made of plainly dressed stonework.

During 1849 an adjacent two-span bridge was constructed to carry the Manchester South Junction and Altrincham Railway over the Irwell.

The viaduct had a large circular cast-iron support column set on a central river pier.

A section of the chord is carried on a viaduct across the Irwell, where it bisects the Manchester end of the Irwell bridge approach and the original L&MR tracks into the Museum of Science & Industry (the former Liverpool Road Station, which was closed to traffic in 1975 and opened as a museum in 1983), severing the former station's connection to the railway network.