About 1/2 mile beyond the possible water tank site is a switchback heading down the mountain:
I parked the bike and hiked downhill. The upper leg of the switchback is about 1/2 mile long. About half way down is this small cut:
Nearby were several used cans of blasting powder from the Hercules Company:
I found many of these cans along the right of way near places they would have needed to to blasting work.
A more modern dirt road follows the grade, but it cuts off the last part of the switchback. This last part is so covered with brush that it was impossible to explore the tail track:
You are looking back towards the tail track from the lower end. Not only was it brushy, but a water course follows the grade...
To be continued...