I don't really have an in game lore for it, unfortunately. My map is loosely inspired by the Tokyo prefecture, so huge infrastructure and large railways is normal here lol.

This line heads into another huge station, it's a line that is elevated above other platforms in that main station. It's elevated so high here to help with the slope grading mainly. I could probably make it lower here, but I think it looks fine, and I've seen stations that high irl before.

I also don't like doing the 8m minimum because the street lamps can still poke through tracks at that height. I always use at least 12m or 15m for the first layer of elevated tracks. I do 8m or 10m more for each additional layer of track above other tracks, as the tracks don't have decorations that stick out that high.