“AMERICA’S RAILROADS DELIVER THE GOODS” is an old advertising line… and it’s true. From the container ports on the coast, those containers ride the rails to their regional destinations. There are huge railroad yards dedicated to on- and off-loading container traffic.
George Ure at Urbansurvival.com sometimes posts economic data from the ports, and also railroad car loadings nationwide. The rail car traffic is a good indicator of economic activity.