Rail transloads operate no differently than airports. They bring many products to one location very efficiently, and then the products are dispersed quickly to their final destinations.
The overall cost of the transportation move is less. There are many reasons for transloading and they depend on the company, the location, and the available transportation options. But the most common include time efficiency, cost efficiency, increased flexibility, accommodations for variability in the various portions of the transportation network, and better rates.
For most companies, it is about determining the true cost of the entire transportation network and determining the options to reduce the cost on the movement and storage of goods.