Its just "temporary equipment", it went back in early September. Here is the thread on www.socalrailfan.com...
I come bearing pictures I have quite a few. Also have some of the AOE stopped in Fullerton station, will post them soon.
I know that there are also SD40-2's, and a Dash 8-40CW #882. I've also seen am MP15DC #3702. Is this the GP50 you were looking for?(This isn't...