That is the training center for the blue angels. When were out hunting ducks on the river, they come by usually at least once a day from that exact area, they seem to use the river for there boundry, or they just like flying it low, El Centro NAF. When you watched Top Gun when a kid, this is that exact area they dropped from Miramar into the dogfight training ground area. All around where i fly is called Proving Grounds. Countries from all over the world come out there to dogfight. All the marines go hike through there before being deployed, it is exactly like the middle East with the hot low desert, high cold mountains around it, and San Diego an hour west
That train track hasn't worked since i was a kid. I'm 99% sure that is the "3:10 to Yuma" track from back in the settling days, just after where i'm at it crosses over into mexico to go around the mountains and to pick up stuff then passes into San Diego. i saw something on the news years ago they were restoring the San Diego area of it and selling passenger car tickets to go through all the old caves and stuff. I kinda remember as a kid, musta been early 80's, we had an El Nino year where it poured and poured for weeks. All that desert area got wiped out. The old road runs right along the track and it's mostly washed away and nobody came to fix it, they just made a new one next to it