the light at the end of the tunnel: is a train.
https://youtu.be/prLs-CHE4Gk
https://youtu.be/5TXq0MSiWVU?list=PLW5vMzzOE6CIAx-cR-ocm1X2PK8PNCuRn
https://www.youtube.com/watch?v=RBdVcI6UxkI