6 ms·

What's going to happen to your latency when you have to wait before you're able to get on the escalator because it is already at max capacity?

jbmorgado 10y ago
That only happens in very specific places at very specific times.
- notacoward 10y ago
  Very common places and times, actually. The tube, like everyone else, builds capacity for peak load. That means there almost certainly will be periods every day when the system is at or near capacity. That's when decreased throughput turns into increased latency via queuing. The only time that's not true is when the system has infinite queues or never approaches peak load, neither of which is a very useful assumption.
  - 4ad 10y ago
    > That's when decreased throughput turns into increased latency via queuing. Only for the people who stand, not for the people who walk, because the people who stand and queue up leave passage for the people who walk to pass through. I can't comment on arbitrary metro systems around the world, but where I live this always happens. When demand is high, people who stand queue up for the escalator, but there is always enough space for people who walk such they are unimpeded. Very rarely demand is so high that people queue up for the trains themselves (only saw this twice in my life, I think), but even then, there isn't any congestion on the stairs.
    - notacoward 10y ago
      In my experience - many systems all over the world, though none as a regular commute since 1995 - the clot of people queuing to stand often severely impacts ability to reach the walking side. An even bigger impact is people who aren't good about standing all the way to the right, impeding progress for the walkers on the left. This phenomenon seems to get worse as queues get longer, though that might not be the case in London with its notoriously strong social norms. In both cases, though, a lack of sufficient throughput does impede walkers as well.
lmm 10y ago
You can get past onto the walking side - the standing side hits capacity first and so only people who aren't in a hurry are delayed. (I see this every morning at Canary Wharf)
- 4ad 10y ago
  Exactly. In my life I have never saw a congestion on the escalator. At rush hour, poeple who stand, queue up, sure, but they never queue up enough in order to block the passage of people who want to walk. Even on New Year's Eve, where demand is highest and the trains are overloaded, I haven't seen congestion on the stairs.
  - Symbiote 10y ago
    Escalators in some London stations are sufficiently congested every day for people to be queuing to get onto either side.

jbmorgado 10y ago

That only happens in very specific places at very specific times.

notacoward 10y ago
Very common places and times, actually. The tube, like everyone else, builds capacity for peak load. That means there almost certainly will be periods every day when the system is at or near capacity. That's when decreased throughput turns into increased latency via queuing. The only time that's not true is when the system has infinite queues or never approaches peak load, neither of which is a very useful assumption.
- 4ad 10y ago
  > That's when decreased throughput turns into increased latency via queuing. Only for the people who stand, not for the people who walk, because the people who stand and queue up leave passage for the people who walk to pass through. I can't comment on arbitrary metro systems around the world, but where I live this always happens. When demand is high, people who stand queue up for the escalator, but there is always enough space for people who walk such they are unimpeded. Very rarely demand is so high that people queue up for the trains themselves (only saw this twice in my life, I think), but even then, there isn't any congestion on the stairs.
  - notacoward 10y ago
    In my experience - many systems all over the world, though none as a regular commute since 1995 - the clot of people queuing to stand often severely impacts ability to reach the walking side. An even bigger impact is people who aren't good about standing all the way to the right, impeding progress for the walkers on the left. This phenomenon seems to get worse as queues get longer, though that might not be the case in London with its notoriously strong social norms. In both cases, though, a lack of sufficient throughput does impede walkers as well.

lmm 10y ago

You can get past onto the walking side - the standing side hits capacity first and so only people who aren't in a hurry are delayed. (I see this every morning at Canary Wharf)

4ad 10y ago
Exactly. In my life I have never saw a congestion on the escalator. At rush hour, poeple who stand, queue up, sure, but they never queue up enough in order to block the passage of people who want to walk. Even on New Year's Eve, where demand is highest and the trains are overloaded, I haven't seen congestion on the stairs.
- Symbiote 10y ago
  Escalators in some London stations are sufficiently congested every day for people to be queuing to get onto either side.