I am not tempted , but I have raised the question of trains many times and note that Bacchus (pass me a microscope please) have added a train set to their Wild West range.
All the main 6mm manufacturers do trains. I suspect that Pony Wars will need one.
The del Prado N-scale static 'Locomotives of the World' series have been mentioned numerous times. There is a 'The General' loco that would be just right for Wild West. Rolling stock might be more difficult, or maybe the Boer war ones would be OK?
A 10mm gamer saying pass me a microscope about 6mm. Behave! Currently painting 28mm Prussian infantry for Bello Ludi Rifles. Have previously painted them in 15mm, 10mm, 6mm and 2mm. Just different techniques for different scales, and I always use magnifiers whatever the scale. Of those I would say for the FPW the most useful were 28mm, 10mm and 2mm.
We get regular requests for trains but it's just not viable based on the sculpting costs we've seen in the past. 3D design might be an option going forward but I'd need to have a chat with some designers about that.