For the last year, I’ve been researching a very niche railroad, that of Sutro Tunnel. Near Dayton, NV.
You won’t find it with web searches, because it didn’t materialize as a legit or public railroad.
But it was there, and huge – but underground, and not connected.
Today, I delivered my lecture on it at the annual V&TRRHS conference.
If someone would like to see my presentation, PM me.