Tower Bridge as its northern landfall is in Tower Hamlets. The bridge consists of two bridge towers tied together at the upper level by two horizontal walkways, designed to withstand the horizontal tension forces exerted by the suspended sections of the bridge on the landward sides of the towers. The vertical components of the forces in the suspended sections and the vertical reactions of the two walkways are carried by the two robust towers. The bascule pivots and operating machinery are housed in the base of each tower. Before its restoration in the 2010s, the bridge's colour scheme dated from 1977, when
Tower Bridge Corporation of the City of London. In 1974, the original operating mechanism was largely replaced by a new electro-hydraulic drive system, designed by BHA Cromwell House, with the original final pinions driven by modern hydraulic motors and gearing. In 1982, the Tower Bridge Exhibition opened, housed in the bridge's twin towers, the long-closed high-level walkways and the Victorian engine rooms. The latter still house the original steam engines and some of the original hydraulic machinery. A computer system was installed in 2000 to control the raising and lowering of the bascules remotely. It proved unreliable, resulting in the bridge being