Re: Narrow Gauge photographers?

Those photos are public domain.
The new copyright law came into effect in 1971 which automatically gives copyright protection until 76 years after the death of a creator of a work or photo. Before 1971, their copyright only lasted 26 years, and unless extended for a one time re-copyrighted for another 26 years, it became public domain.
Most postcards are not copyrighted unless they say so, with c in a circle and a DATE.
Just show credit: Photographer-Unknown.
Giant thief of photo copyright go unchallenged so why are you worried? One big example is a giant mural painted on the under track entranceway for passenger training in Denver Union Station. Some thief stop Bob Richardson photo of the next to last RGS train crossing Franklin Jct. Trestle and Bob was never credited in that giant painting copied exactly from Bob's photo he got from DPL.
It was in a light snow and Bob distinctly rembembers that there was no snow tracks in the road to that place so another photographer could have been hiding in the bushes to take the same photo. They had a big dinner shing-dig to honor the painter of the mural but not one crumb to Bob.
He got paid big bucks and never gave Bob a nickle.