And trains now running every 3 minutes at peak times

Up to 28 tph (so almost every 2 minutes) at say Stockwell, because it has 24tph from the Bank branch and a few extras from the Charing Cross branch all going South. Most Charing Cross trains come out of service at Kennington (otherwise it would be 48 tph which would be entirely crazy) but not all of them.

Victoria line is running at 36tph at peak times. I believe that's the most anywhere in the world (tied with a line in Moscow I believe?).

Paris Metro Line 1 can run ah 42 tph.