The growth of double-stack intermodal trains has been one of the greatest economic developments this country has seen in the last few decades. The "congestion reduction" benefits are meaningless. The biggest impact is the reduction of shipping costs over long distances.
Two double-stack projects in particular -- the Pennsylvania Clearance Route (1990s) and Heartland Corridor (ongoing) initiatives -- have enhanced Midwestern cities like Columbus and Chicago as major warehousing and distribution hubs . . . simply by providing double-stack rail access to the ports of New York and Norfolk.
Lots of talk about big cities but I still fail to see any advantage for flyover country.