There was a little alley in San Francisco back of the Southern Pacific station at Third and Townsend in redbrick of drowsy lazy afternoons with everybody at work in offices in the air you feel the impending rush of their commuter frenzy as soon they'll be charging en masse from Market and Sansome buildings on foot and in buses The author includes these details to compare lazy afternoons with hectic work days. describe San Francisco just before rush hour. clarify how employees commute to their offices. explain his job at the Southern Pacific station.
These details are included by the author to describe San Francisco just before rush hour. It is in the excerpt that there is still a calm pace of people getting ready to be busy and rushing on their works. This explains how people are preparing for the rush hour.
