I am trying to remember the title of a film in which a boy invents a battery that never runs out. The film includes a fight in a train kitchen. The battery, which turns out to be flawed and gets warm, explodes in a helicopter and kills the bad guy. The movie’s hero tucks away this inventor boy in a container, and when the boy is kidnapped, the hero interprets the writings on the container’s walls, and manages to locate him. In a train, I think.
Ring a bell, anyone?