Here's something you don't see everyday...a photo of a covered railroad bridge. Photo taken c. 1935 in New Hampshire. It was on a Boston & Albany line.

FYI...there are still a few covered bridges here in New England. I believe most are for road traffic. Storms through the years (over rampaging rivers), fires and expensive upkeep have been some of the primary reasons thru recent decades of their demise. Most of those still standing now are respected historical sites ;-)