A Muni light rail train (sort of metro-tramway) going fast in the Duboce Tunnel, also known as Sunset Tunnel (San Francisco).
Watch the video and listen to the audio track!
There is not enough clearance between the train and the tunnel walls, so you *must* hide in a small alcove when you see a train coming.
No trespassing! This is REALLY a DANGEROUS place!
For more information about this place, read: en.wikipedia.org/wiki/Sunset_Tunnel