Tips for Train
I recommend to start at some basics. Don’t design a fancy train system right away.
In that regard, a 2-locomotive train that travels on one railroad path (so that it can pull the train forward and backwards, relative to your path’s thinking but to the train, it’s still just going forwards since you have a locomotive at each end), works very well for beginner bases that are just trying to get more resources back to the first base. It is enough functionality to let you keep growing your base, including just to get more railroad resources and bots to make bigger and better railroad networks as your base grows.
The main thing to get right even in this basic setup, is where the train stop is (on the right hand side of the tracks) and then how to load/unload items (at the boundary of where each train car rests when you’re at the train stop)
Later on, you can make a railway with loops at a destination, so that just 1 locomotive is needed, and even later after that, go for a design with 2 or more railways, each giving the trains their own direction of travel (and if you want to do that, just place down some small sections of railroad to give you the idea of how much space to allocate)
I say it this way because if you’re constantly getting stuck here at needing/wanting the train but not understanding the train, making you discouraged from continuing on, then this kind of basic train system will give you encouragement to keep on going,
Later when you have an army of bots on your personal equipment, it won’t be a problem at all to redesign a better train system (including just to use some publicly available blueprints which will make more sense after you’ve learned the train logistics a little better)