Tunnels...

Rimutaka Tunnel, New Zealand

https://www.youtube.com/watch?v=GOK5LhaNxLA

Canadian Pacific Railway's Mount Macdonald Tunnel 

https://www.youtube.com/watch?v=UjE6qhoSQHM

The Secret Station - Aldwych

https://www.youtube.com/watch?v=6xSzU0oM4mM
lon tube
https://www.youtube.com/watch?v=Z1q8nJXk_ZU

London Underground Freight Train

https://www.youtube.com/watch?v=kbzPYA6dvWg