There is still some ATSF power around, and if you're willing to poke around, a number of the GP60's and GP39-2's assigned to locals are still in ATSF paint. I've had decent luck in the San Joaquin Valley with some of the locals based there, though I have not been through there in a year plus. Things are indeed changing, and best to shoot these units when you can as who knows how much longer they will be in their ATSF paint. Below is a shot of the Evening Kings Park Local:
Kings Park, CA by
Matt Batryn-Rodriguez, on Flickr
Take care,
~Matt