Plot hole: The manner in which the Microwave emitter is used to vaporize the city's water would not go as intended. Microwave emissions coming from a device located inside of a train that has a very metallic exterior will unavoidably be affected by the photoelectric effects resulting from any microwave beam that is focused at the water mains below the train from within it. A fork placed within a relatively low powered kitchen microwave would encounter a similar effect.
RootofInsanity
11th Jan 2012