this is only a problem in japan because the shinkansen is the oldest high speed network in existence.
new train tunnels built in Europe are wider and flare out at the end so that there isn't a tunnel boom.
new train tunnels built in Europe are wider and flare out at the end so that there isn't a tunnel boom.
> Basically what happens is when a train enters a tunnel at high speed, the air in front of it is compressed and does not have enough time to flow past the trains body. When all released at once, the pressure causes a shockwave that goes boom!
This is basically a very rudimentary version of the piston effect: https://en.wikipedia.org/wiki/Piston_effect