One of the more interesting tunnels on the South Pacific Coast Railroad is Tunnel No. 5 in Zayante.

This is one only two tunnels on the former South Pacific Coast line that is still in use, although not by a railroad.

As the railroad climbed its way up Zayante Creek it came to a granite outcrop that the builders could not go around or over so they had to tunnel through it.

Granite is stable and solid and because of that they did not have to add any interior wooden supports. When completed Tunnel No. 5, at 250 feet, was the second shortest on the line.

The tunnel was active until the Southern Pacific’s abandonment in November of 1940.

The tunnel began it’s current use in 1952 when the Western States Atomic Vault Company bought the tunnel, sealed both ends and used Tunnel No. 5 as a fire-flood-nuclear-proof storage silo, housing records (mainly microfilm and microfiche) for many companies including Disney. The silo officially opened on May 2, 1954.

The eastern portal was made the entrance to the facility and a guard shack was built (featured sketch) where a guard was stationed 24/7. We did not see any signs of a guard so we could not ask for a tour. (The facility is currently owned by Iron Mountain).

In times past, the company would allow tours inside the facility and one visitor deemed it the “most interesting dull place in the world”.

One can only guess the nearly 70 year old “secret” files that now reside in the former railroad tunnel known as Tunnel No. 5.