Here is a great view of the icing process. Note the bags of salt, the boards used to slide the ice cakes onto the reefer, the tools used and the number of people involved. There must be 40-50 people in this one view alone. Imagine how many people were involved from S. Cal to Chicago
ORIGINAL CAPTION
"Comprehensive view of Santa Fe's large icing facilities at Bakersfield; CA. Ice manufacturing and storage facility appears in the right background. Icing docks and conveyors appear in the foreground."