I've actually seen many "knock-off LEGO" sets that have trains that work on LEGO tracks and use LEGO train wheel elements. I couldn't tell you the brands, but I bet you'd find them somewhere. I also know that there are some sets of instructions online for different types of LEGO trains, in pdf, physical, and video tutorial forms.
I've also heard of a website many times called Big Ben Bricks which, from what I can gather while still being too lazy to look it up myself, LEGO trains, especially wheels.
Creator of upcoming series "Sudrian Tales"
Amateur voice actor
Still haven't painted FFF's Daisy lol sorry my guy (i promise I'll get that airbrush kit soon)
Do you know Beanmeister22? He used to have videos on all of these brands that showed how good (or bad) they really were before you bought them. There were also comparisons between each one, including track systems and specific engines/rolling stock.
Big Ben Bricks is a company that produces third party, LEGO compatible wheels for building realistic steam engines. Their wheels actually predate the official ones made for #10194 Emerald Night.
No sweat Super I'm a lego ninja, been making the things for decades lol!
Happily collecting things all my life...