The author of the original mod is Valkhiya. He has been inactive for over 2 years, so I have updated his mod for the new game version. The modification needed some changes because now we have train ramps, so there are new sprites. You can also choose from 2 sets of sprites, one is even more saturated than the standard one. The more natural look is the default.
Original mod:
https://mods.factorio.com/mod/vibrant-trains?from=search