Ships are very energy efficient, shipping will last longer then any other kind of freight.

And we might build a flotilla of very large and very fast nuclear powered container ships to tie togeather the worlds rail networks as a replacement for airfreight.

I've been thinking along those exact lines.  It seems that the Russians are missing the boat, so to speak.  They have plenty of cheap maritime reactors in their obsolete submarine fleet plus low labor costs.  A high speed, nuclear powered container ship on the trans-Pacific route could do more turnarounds per year and offer faster service.

A problem would be faster on/off facitilites at the ports to better exploit the ship's speed and minimize port stays.