A Southern Pacific train chugs up Alameda St at 2nd St, which puts it a few blocks south of where Union Station will later be built on the edge of downtown LA. There is a flagman on the left helping to control traffic. I’m guessing those workmen on the left are laying down a third track along Alameda. Between the trains, the regular traffic, and the construction, this shot was probably taken amid a deafening din.
The California Hardware Company building on the left is still there. This image is from June 2022.