I cannot believe it. Indeed TÜV SÜD also certifies tunnels. Among them are very very critical tunnels. I hope they are properly checking the safety in those tunnels, considering what happened in Brazil...

Their web site lists some tunnels (screenshot)

Here is the list of tunnels whose "safety certified" by TÜV SÜD:

Turkey: MARMARAY TUNNEL ISTANBUL

website says ' Our colleague Dr. Valentina Monaco from TÜV SÜD Rail is responsible for safety on the project.'

You know what? This is mostly not a bored tunnel but a submerged one. It was built by a Japanese company. I hope TÜV SÜD is doing their job correctly.... Damn!

Switzerland: Tunnel operation – safety assessment of existing vehicles

https://www.tuvsud.com/en/e-ssentials-newsletter/rail-essentials/e-ssentials-2-2018/tunnel-operation---safety-assessment-of-existing-vehicles

Safe travelling at record speed - Prestige project VDE 8 on trial

Europe wide work:

https://www.tuvsud.com/en/e-ssentials-newsletter/rail-essentials/e-ssentials-1-2018/safe-travelling-at-record-speed---prestige-project-vde-8-on-trial

Sweden: Västlänken Tunnel

Including 6km long tunnel: https://www.tuvsud.com/en/e-ssentials-newsletter/rail-essentials/e-ssentials-2-2016/tuv-sud-won-project-vastlanken

Austria: Wiener Linien

https://www.tuvsud.com/en/e-ssentials-newsletter/rail-essentials/e-ssentials-2-2018/metro-and-urban-rail-systems---a-passenger-safety-assessment