In 1991, the Docklands Light Railway was extended to Bank Station, following criticism of the original, poorly connected terminus at Tower Gateway. The new platforms were built parallel to but deeper than those of the Northern Line, with connections at one end to the Central line and Monument Station at the other. As part of the construction of the extension, a new link between the Waterloo & City and the Central line was excavated – uncovering part of one of the Greathead tunnelling shields used for the Waterloo and City line. This shield forms part of the new passageway, and passengers pass through when transferring between the two lines. As with all other DLR stations, the DLR platforms are accessible, however the route is indirect with the use of three different passenger lifts required to reach the DLR.