>TWO more questions, where was the tower at redwood jct located?

East side of the tracks (the Bay side) almost underneath the overpass.

>And what is the deal with all the very short passing sidings along the route?

The "route" is Redwood-Tracy, via Newark and Niles, and it's all Western Division. As for the sidings, you're going to have to be a little more specific. There were none between Belle Haven and Shinn, other than the previously mentioned "Dumbarton Siding" which wasn't really defined as a siding in later years (see next paragraph).

A "siding" has to be designated as such in the timetable, otherwise it's just another track, referred to in rr slang as a "runaround", provided it has a switch to the main line at each end. A "siding" can also be single-ended, although this wasn't very common on steam (and diesel) railroads.