It's hard to tell where this is from the background. But,there are probably only two highly likely candidates around this time: 1) J Yard/Butte Street, or 2) 8th Street-on thee PE side (LA Produce market today)?

The PE was once a very a big freight railroad, with lots of yards, at one time. And some of these were gradually absorbed into the SP and still being used, while others were mostly abandoned by this time. Even Butte Street was just the PE side over to Long Beach Avenue with a couple of tracks to switch cuts, tie down the engine, and the main tracks down to Watts Junction, with almost all of the rest of what had been Butte Street gone by this time.

PE technically didn't have yard service employees, they had "train crews". So while from an operational standpoint most of these "yards" were Rule 93 territory, and were used to switch cars, in downtown LA, at places like 8th Street-the PE side was "conductor/brakey" "road" territory, where as on Alameda, o the SP side at J Yard, it was "foreman/switchmen" "yard" territory, for union crew and pay rate purposes.