If you want to know why Paddington Exchange fllooded here is the explanation:

A lot of the switching equipment is stored in the basement of the exchange. The building, like many others in London, has lower floors which sit below the water line. Pumps are installed so that should any of the water leak into the base of the building, the pump automatically kicks in to get the water out. This obviously didn’t happen in the case of Paddington North yesterday, either because the pump was faulty or there was a more major kind of water leak. (more…)