Most express trains in other countries just use different tracks at certain points (or run parallel depending on the system). The idea is good, but an “express” line in this case seems like it would have to be dependent on the regular lines for quick service. I could imagine a scenario where every third train makes regular stops, while the two express lines in front go to the busiest stations. That still relies on an earlier regular train not being delayed. Honestly I think express lines would make commuting for me so much easier, but unless they’re laying down more track, or tightly honing their schedules, I’m a bit skeptical.