Thank you for the additional information on Tunnel 13. I do have one point of discussion however. I would argue that this is not the second tunnel at this location, but rather the same tunnel repaired after the problems in 2004. One does not have to shine a light very far into the tunnel to realize where the rock falls were located and have since been repaired. It is not as if there is another abandoned replaced tunnel near by, The Central Oregon & Pacific just fixed what they had to, in order to open the tunnel back up.
I did not know about the additional rail alignment located to the east. That is interesting. Do you have any photos of the old bores?
This is actually the second Tunnel 13 at the site. A few years ago, the timbers under the gunite lining caught fire and the tunnel partially collapsed. It took CORP several years to rebore and reline the tunnel, and not long after they embargoed the line south of Ashland, which makes you wonder why they bothered to reopen the tunnel in the first place.
Only a few miles away are the incomplete bores for the Buck Rock tunnel, which was begun, as well as tunnel 13, by the Oregon and California railroad just before it went bankrupt. When the railroad resumed construction, the Siskiyou line was rerouted up the other side of the mountain from the original grade, and tunnel 12 was abandoned half fished, but tunnel 13 was completed. If you go looking for the Buck Rock tunnel, it's not hard to find. The north portal shows on the USGS quad map as a mine shaft, but it's not. And there is a road leading over the ridge to the south portal. There is a bit of unfinished railroad grade leading out of both portals, too.
The Siskiyou line originally would have diverted from the current route at Dollarhide Curve, and climb eastward up the side of Buck Rock, passing thru three small tunnels. We have found no trace of the lower tunnel so we suspect no work was done on it, but now that I think about it, we had been following the wrong part of the grade to find the lower tunnels. The railroad would have passed around Buck Rock and back through the ridge via the Buck Rock tunnel and climbed the ridge back to the current tunnel 13, passing through one other tunnel along the way. Since the Buck Rock tunnel is pretty well known here in Southern Oregon, and none of the other proposed tunnels are ever mentioned, I suspect they were never begun.