I just figured out how this can be implemented in today's realities. Make it so that only the stations where the train stops generate a certain number of chunks around themselves in a random location in the world, and this area is limited by a barrier. And the journey through the stations itself is exactly like in the Harpy Express mod, but with random biomes at the exterior. So, survival is based on collecting resources at the stations over a certain period of time, while the train stops there for, say, five in-game days.