A signal failure is causing severe delays on the Elizabeth Line, but the Tube and Overground trains are otherwise largely running normally again after flooding caused numerous lin

The network south of the Thames relies on a “third rail” for the power supply, which Network Rail says is vulnerable to flooding: “When flood water rises above the rails, trains have to reduce their speed to prevent damage to the train. Flooding can cause a short circuit and cut the power if the track has a live conductor rail.”

London commuters had to endure a day of chaos and disruption after heavy rain caused widespread floodingPart of the District Line and London Overground have been suspended all day, after heavy rain hit the capital’s transport network overnight.