Once in place, the separate lengths of tube were joined to form parallel prestressed continuous structures, each one possessing a length of and weighing . The pre-stressing process had increased the structure's loadbearing capacity and reduced deflection. The tubes had a width of and differed between and in overall depth, while also having a gap between them; they were supported on a series of cast iron beams that were embedded in the stonework of the towers. To better protect the iron from the weather, an arched timber roof was constructed to cover both tubes; it was roughly wide, continuous over their whole length, and covered with tarred hessian. A wide central walkway was present above the roof for the purpose of producing maintenance access.