Will it work on SBB trains and through tunnels?

The ETravelSim Switzerland eSIM works on SBB Swiss Rail trains, including most intercity and InterRegio routes, with strong 4G coverage along major corridors like Zurich-Geneva, Basel-Lugano, and the Glacier Express route. Most rail tunnels including the long Lötschberg and Simplon tunnels have signal-boosting infrastructure. The Gotthard Base Tunnel may see brief connection transitions during the deep crossing. The SBB Mobile app works fluidly throughout Swiss travel for live platform changes, ticket QR codes, and connection updates.