Nice map with not ordinary concept (two lines, more bonuses), but a little boring at the end. Like the idea to variegate gameplay on Mini Metro.

Nice map.
I was trying the two-line challenge. At game end, I converted to Endless Mode and took lots of upgrades, including three of the four remaining New Lines. Soon after, I got more upgrades and was offered a New Line in the first set - I took it.
However I was then offered a New Line in the second set (when I had all the Lines), and then the New Line icon remained in the middle of the screen as play resumed. It stayed there even as I exited to the main menu. I had to shut down to get rid of it.

Maybe the game doesn't re-check for Lines at each step of a multi-step upgrade?

Good map with decent spawning and reasonable but not too challenging achievements!