The north classification yard is not as abandoned as first appears. There are two men in the center foreground, huddled over working on something together. Then, straight up from them and a little to the right, is a man walking the tracks. Beyond him, where the railroad cars are, I count 10 men walking (I'm pretty sure they're all men).

I hoped to see one of the control (switch?) towers occupied, but no.

This image shows the many power switches and retarders used to direct and control the speed of cars that have been shoved over the top of the hump and roll by gravity to their intended classification tracks. The hump yardmaster (located behind the photographer) arranges the switches and retarder operators (in their small towers) slow the cars by squeezing their wheels so that they roll their intended distance before coupling up to cars already in the track. Wind, different car weights and number of cars already in the track require a lot of judgment to prevent a car from "stalling" before reaching its intended destination or rolling too fast and slamming into a standing car.