You are right, it does appear that the industries at the far eastern end of Carroll Avenue are no longer rail served judging from the asphalt in the flangeways. The switch appears to have been lined for the spur that goes into that fenced area with the trucks, through what appears to be a gate.
My guess is that UP uses the street trackage opposite that warehouse as a tail track in swapping out empty reefers for loads much as Chicago Terminal/CP/MILW did with the street track on Lakewood in Chicago when working Peerless.
It would be priceless to see traffic, including a streetcar, stopped for a freight train.