The unreal science of Japan's 400kph bullet trains explained

The ALFA-X, Japan’s next-generation bullet train, will hit speeds of up to 400kph. But why does it look so weird?

The nose is designed to combat what engineers call the ‘piston effect,’ caused by trains pushing air through tunnels as they enter. “It’s like a piston going into its cylinder,” explains David Soper, a lecturer in vehicle aerodynamics at the University of Birmingham’s Centre for Railway Research and Education. “As the train enters into the tunnel it sets up pressure waves – it comes down to train shape, length, and speed.”