What are you going to do about the areas that are more than 50 miles from a train depot? Haul it in several smaller vehicles? Sounds efficient...whats better 60,000 lbs hauled at 8MPG in one truck or 10,000lbs hauled at 15MPG in 6 vehicles.
There is a reason we are still using trucks...good luck without them.
I think you really underestimate how big this country is and how small a 50-mile radius is. That kind of coverage would be absolutely impossible to do.
You're not terribly familar with the existing freight infrastructure in the east coast then.
Look at a map of Pennsylvania, one of the larger and more sparse eastern states. 50 miles from any point will get you to Erie, Pittsburg, Philadelphia, Harrisburg, Allentown, Scranton, etc. All of which you can ship and receive freight by train from.
And that is a bad example of a state where it could work. Try looking at Jersey instead!
There is a reason we are still using trucks...good luck without them.