After seeing several pictures from the area I decided we needed to check this out. On the wat down from FR300 we missed the turn left to the actualy train trail. However, a little further down is the sign marking the turn (a right turn) for the people hiking up from below the rim. We turned there and found the tunnel. It actually made the hike a little longer for us this way as we just were on the col devin 290 trail a bit longer.
Once at the tunnel it was nice. just like the description, cool inside, sandy floor. In fact the sand was damp, and the last 10 ft or so of the tunnel was a big puddle.
On the way back, we found the right trail headed back up the mountain. This was quicker, and then we also found where the cut over is from the original trail. Atleast now I'll have right for the next time.
After the hike we were chillin at fr300 and a FS guy rolled up, he chatted with us and was asking the condition of the trail, if there was a sign in box, etc. Afterwards we drove to the general springs cabin and then patato lake and found a few other trailheads to check out on another date.