It is done. Instead of adding another line as I planned, I realized how exhausted I was of working on this enormous world. This was after of course realizing my failure in designing a completely automated system. Because it's not possible as of right now. Unless players were able to have 100,000 chunks loaded at one time, there's no way to keep minecarts moving outside of loaded chunks. Then I realized that the command I was using to stop the minecarts in the station doesn't exist anymore in Minecraft 1.13.2. And so I decided to take the Metro System World back to its routes. It's simplicity. The new design is simple, and the stations are more inviting, brighter, and overall nicer. This was never a perfect build, but it always has managed to stick around. And finally, after about 5 years of off and on work, it's done. Check out the map for yourself for the full experience.