I made it to about 2050 when I got really tired of traffic jams, and I never got to 1k population. It sort of fluctuates, I can’t get a ‘perfect’ growth. I tried long lines that go everywhere, also shorter, specialized lines. Generally speaking coverage is good. Although maybe it’s just way too micromanagement to rebuild each city’s lines every 10 or 20 years 🙂
Maybe in my next game I’ll try more trains to connect cities instead of trams that I use now, these really struggle in traffic late game.