Underwater tunnel. Computer artwork of a long distance underwater tunnel. The tunnel, which is neutrally buoyant, remains secured in place by vertical tethers attached to floating pontoons (not seen). Transport such as maglev trains could travel at high speed without stopping until reaching their destination. A journey from London to New York (5,585 kilometres) in a maglev train travelling at 500 kilometres per hour would take 11 hours. If built, tunnel engineers must overcome the difficulty of building the tunnel in mid-ocean. It must also withstand the enormous pressure of water at depth and overcome the forces of ocean currents and storms.