[hifromLA]

I disagree. Look at something like the Chicago el which is a true hub and spoke system. The el needs a ring line since any trip that doesn’t start or end in the loop generally requires taking the bus which is fine but not rapid transit.

By contrast look at the Yamanote line in Tokyo for a great ring that provides tons of connections and gets tons of ridership.

[angled]

Beijing has two rings for its metro, and has 5+ ring roads. I could never live there but as a tourist the metro works well!

[seanmcdirmid]

Beijing has 6 official ring roads. There is also a 7th but it isn't considered part of urban Beijing.

It really does suck. I lived between 3rd and 4th ring road in the eastern mid section (around san yuan qiao), and my work was on 4th ring in the northwest section in zhongguancun. So...around the loop I went, it makes the trip 20-30% longer. Line 10 (a loop line between 3rd and 4th ring, line 2 would be the inner loop around 2nd ring) theoretically takes me straight to work from near my house, but I almost never took it because it was just too long (and it was just easier to sit in a taxi on 4th ring if I timed my to work and from work time right).