Runaway is an episode of Thomas' Adventures of Thunderbirds Are Go ( 2015 TV Series).
A high-speed test train on a Japanese Maglev line suddenly goes out of control, and is in danger of running into the back of a passenger train. Only Brains and Toad can stop it, so they set out with Duck, Oliver, Thomas, and Scott on Thunderbird 1 to board the train. But in doing so, they discover the train is under the control of an Artificial Intelligence program, which John determines is playing a game. Toad, the engines, Scott and Brains must find a way of stopping it before it crashes into a station terminal.