The travel-related stuff is on the Smithsonian Channel now. Example:
https://www.smithsonianchannel.com/details/series/mighty-trains
We now return to Stone Axes, on Modern Marvels.
At least, when they aren’t running Air Disasters or Disasters at Sea. 
But, overall, I do like a lot of Smithsonian’s programming, including Mighty Trains, which is about great tourist train routes all over the world.