Does the US Postal Service still use trains (rail service) to move mail around the country? I thought they only used trucks and planes, but I may be wrong about that.
It appears that they largely stopped using rail to move mail in 2004 when Amtrak abandoned the non-passenger aspects of their business.
This “Who we are” PDF from the Post office indicates some mail is moving on intermodal freight service, but it doesn’t really describe how much or under what conditions.
The U.S. Postal Service Office of Inspector General would like to see more mail on the rails, as detailed (and I mean detailed) in this recent report. (also a PDF)