These aerial photos can be a bit tricky. The ATSF spur into Del Monte is definitely still there as far as the crossing of the road. Whether the track actually connected to the rest of the Del Monte spurs is questionable. Here's two frames from the 1965 flights. You can see that there is some stuff built across the rails within the Del Monte plant. It's hard to tell whether these are elevated or not.

15 115 (which you've looked at):


And 15 136 which shows the Santa Fe lead a bit better due to glint but you can't see the tracks within Del Monte because blocked by plant building. To download the high res version here's a link: [mil.library.ucsb.edu]