San Diego & Imperial Valley Railroad operations on the MTS Blue Line

In the early morning hours of September 9, 2015 I heard what I thought was the San Diego and Imperial Valley Railroad's NB freight train on the MTS Blue Line so I headed out to the trolley station on Palm Ave. to catch it, but when I got there the signals were red.
Figuring it had already passed I drove down Hollister St. and Industrial Blvd and as I was at the Anita St. crossing, the gates activated and I heard a train coming from the north so I quickly pulled over and caught the SD&IV's SB manifest. I actually never knew the SD&IV operated a manifest that ran to San Ysidro because I had always thought it was a NB train only so this was very surprising. SD&IV 3GS21B Genset #702 & CORP GP38-2 #3827 were providing power. The next place I caught it at was at the Iris Ave. trolley station where it waited for a green signal to proceed to the San Ysidro yard and where it apparently met a NB train, which at the time I thought it was the NB manifest. (I heard another horn and saw a blinking fred when I first got there)
I then drove north to the SD yard to look for this other train but initially had no luck and then as I was driving back home I saw a locomotive switching the Forst Plywood spur in National City, so I quickly got off the freeway and turned around just in time to catch a NB switching local, led by SD&IV 3GS21B Genset #701, at the 24th St. trolley station in National City.
All-in-all, it was an unpredictable and surprising night. But hey, that's the SD&IV for ya.