Emanating from the office of John Wolfe Barry (1836–1918), these duplicate plans were prepared from drawings sent by some of the chief contractors working on construction of Tower Bridge, and offer an insight into the building process of an iconic piece of engineering. The plans include details relating to the preliminary stages of construction – including the positioning relative to barge routes on the Thames, and a temporary staging from 1889 showing the bridge in its entirety – and illustrate the infrastructure impacts of such a project, which demanded solutions for systems ranging from sewage to electrical wiring. Alterations to the stairs and steelwork of the bridge are shown as construction progresses towards completion in 1894. The plans were sent to the office of Wolfe Barry, Head Engineer, from the offices of Baron Armstrong (overseeing hydraulics) and Sir William Arrol, as well as from the office of Sir Joseph Bazalgette, an earlier contender for chief architect on the project. Further plans are marked specifically as having been sent to Barry himself, to his partner in the enterprise, Henry Marc Brunel (son of Isambard), and to George Crutwell, resident engineer for the work. The three engineering instruments are also from Wolfe Barry's office.