There are so many westerns here that it's difficult to sort through them. I started with the idea that if your story featured a well-drawn train, it's more likely to have come from a publisher who hired good "hardware men." So many artists sloughed off complicated stuff like trains.
Two publishers came to mind: Lev Gleason's
Black Diamond was big on Indian attacks. William Overgard and, especially, Dick Rockwell were good with machinery. Browsing through
Black Diamond I found a really nice Dick Rockwell splash that matches your criteria. It's on our page 3 of issue 33:
https://comicbookplus.com/?dlid=21348Is that it?
Quality also had some good hardware artists in titles like
Crack Western. but they don't seem to have been much into Indian attacks. By the way, do you remember whether your story was a lead story or an interior story?