Rails of War mod suggests some good-looking and well-animated trains.
It's been in development for a while and still is, so don't expect it to be flawless or bug-free.
This project is driven by sole developer code-wise, which means updates aren't often. There are several big goals to complete in terms of code, and no strict roadmap.
For now it's narrow 12 tx gauge only, with other gauges coming back later. It's also creative-only.
For live status updates you can check out Discord. There's also a thread on Minecraft Forum and Twitter, but those aren't updated often.
If you want to favour the development, feel free to support the developer via Patreon or just by subscribing to the channels and telling your friends about RoW.