To cope with the increase in traffic this would bring, the station required an extension, the construction of which began in 1881. A number of buildings, mostly along Dudley Street were demolished to make room for it, including a number of cottages, some business premises and a small church. Built immediately to the south of the original station, the extension contained four through platforms and one bay. It consisted of a trainshed with a glass and steel roof comprising two trussed arches, wide by long, and wide by long. It was designed by Francis Stevenson, chief engineer to the LNWR. The extension was opened on 8 February 1885. With its completion, New Street nearly doubled in size, and became one of the largest stations in Britain, covering an area of over .