[danhor]

> and heavily reverse-branched systems like the DC Metro or NYC Subway struggle to make even 20TPH.

I find this really interesting that is seems to be the limit for "big-boy" complicated subway systems, while there are many very complicated smaller systems that achieve much more. For example, a lot of the german Stadtbahn systems run somewhat long trains (up to 80m), run using conventional signalling systems underground (so not on-sight, which would allow for a much higher throughput). Naively I'd assume the tram-style segments and frequent at-grade crossings would make this much worse, but apparently not.

For example, Stuttgart (https://download.vvs.de/Stadtbahn_Liniennetz.pdf, https://gleisplanweb.eu/show.php?Map=Stuttgart&Index=1&Heigh...) currently runs 27 tph between Stadtbibliothek and Olgaeck, with plans to run 30 tph without any upgrades, and 30 tph between Staatsgalerie and Stöckach (additionally even running the U11 for events) without any significant issues and quite a complex network with many flat junctions outside the underground sections. The DC Metro has much less complicated branching/reverse-branching patterns.

[TylerE]

Trams often have rubber tires, which gravely increases acceleration and braking.

Also, 80m isn’t that long. Trains on the the DC metro are pushing 200. 8 cars long.

[danhor]

> Trams often have rubber tires

No, they don't. There are a handful of weird french systems (and even less outside of France), but there are more ruber-tire metros than trams, I'm sure. They are rare and have been getting rarer.

80m is in the lower half for metros, but long in the context of systems having on-street portions (exceeding the german legal limit of 75m with a special exception). It's also on the long end for small metro systems.

[TylerE]

The Stuttgart system is light rail, not a tram. Big difference.