Check out the 10 longest railway tunnels in the world:
10. Iwate-Ichinohe (Japan) Length: 16.0 mi (25.8 km)
9. Hakkoda (Japan) Length: 16.4 mi (26.5 km)
8. Taihang (China) Length: 17.3 mi (27.9 km)
7. Guadarrama (Spain) Length: 17.6 mi (28.4 km)
6. Guanjiao (China) Length: 20.3 mi (32.6 km)
5. Koralm (Austria) Length: 20.4 mi (32.9 km)
4. Lötschberg Base Tunnel (Switzerland) Length: 21.5 mi (34.6 km)
3. Eurotunnel (France-UK) Length: 31.4 mi (50.5 km)
2. Seikan (Japan) Length: 33.5 mi (53.9 km)
1. Gotthard (Switzerland) Length: 35.5 mi (57.1 km)
See Answer