You can track containers on railroad websites. Some require a company login, which they manually approve. Others don't. Some require you to be a 'Notify Party', others don't.

The trains aren't being tracked. Containers are. And not real time. Rather it's a snapshot every 12-18 hours.

Maybe what you're thinking of applies to the trains themselves? Or specific types of railcars?

Can you speak more to this? I've thought about using some ALPR type system to read tanker car registrations from a nearby webcam.