Not sure what Red51 has planned for trains, or what he has modeled up, but I do have a suggestion about what 'could' be added as the first round of things. Basically handcarts at first, then trams on both the passenger & cargo side of things. I say trams would be a good way to introduce trains into Rising World because it gives us things to work with on both a player scale, NPC scale, and even cargo scale that we can start with small gauge rails, then eventually work our way upward. Also, trams would be a good use for inner & outter settlement use for city-to-city use.
Or the Zurich Cargo variation:
I find tram use neat because they're right in the middle line of stuff that they're both basic & heavy at the same time. I've even noticed companies using trams on already existing tram lines to haul goods to and from one headquarter to the next within the same city. Would even be useful for 5,000 distance that you'd be there in 2 min, not 30 minutes by foot. Plus, you'd be able to carry so much goods. Now, the tricky question would be how difficult the recipe would be to craft these trams because they're complex machines.
I guess horses shall do until we can tech up into trams. Even being able to make wooden rails, something that was actually made. I love the vibe I would gain when having a cargo train at hand, something that would also help with the construction of railways until bigger trains are introduced.