H0 Gauge (High Speed) Train Tunnel

I print these on my MK3S with 0.3mm Layer Height and 0% infill.

Tunnels like this can be found on German High Speed Railway like the Schnellfahrstrecke Hannover Würzburg.

https://en.wikipedia.org/wiki/Hanover%E2%80%93W%C3%BCrzburg_high-speed_railway

Update 2022-01-01: Added Straight piece on demand of my son, so you can build excellent tunnels on the floor