Parallel Systems is going a step further, though. Each of its rail vehicles consists of a battery pack, electric motors, four wheels, and a package of sensors that allow it to operate autonomously. And since a large portion of the worlds freight is shipped via 20-foot containers, Parallel Systems is using the containers themselves to complete the car, bridging the gap between the sets of wheels at either end of a train car, also known as bogies.

Source: Autonomous battery-powered rail cars could steal shipments from truckers - Ars Technica

This is really interesting and makes much more sense than driving a semi truck across the country or trying to make autonomous semi trucks a reality.