Comment by decimalenough
7 days ago
40 trains per hour is in fact not "normal", but extremely difficult. Only a few systems in the entire world operate more than 30 per hour.
The fundamental constraint is not technology, but people and physics: you need to decelerate and stop, let people disembark and get on, accelerate and clear the platform. This cycle requires a bare minimum of 90 seconds, although IIRC a few lines in a few places like Paris and Moscow do 85 secs.
SEPTA's T [1] gets up to 70 TPH and used to handle 150 TPH. You can do this with multiple trolleys loading/unloading on a platform simultaneously.
(But this strategy is orthogonal to the article, because it requires long platforms.)
[1] https://en.wikipedia.org/wiki/T_(SEPTA_Metro)
Indeed, the Victoria line in London manages 36 TPH and we've not bothered beating it since. It's much easier to run 26-30TPH with slightly more carriages.
> the Victoria line in London manages 36 TPH and we've not bothered beating it since
That was a world record for a line following modern safety standards, set less than 10 years ago. It's hardly a case of "not bothered", it's just hard.
90 seconds is very possible in new-build lines which is what the author is talking about. You can buy a turnkey Innovia (e.g. Vancouver Skytrain) or AnsaldoBreda (e.g Copenhagen) that does this out of the box. Retrofitting 90s operation is basically impossible but not the point of this exercise.