3 ms·

> The Senior Press Officer added that with many stations in close succession, the Victoria and Central lines experience frequent acceleration and braking, contr

by joshka 1y ago

> The Senior Press Officer added that with many stations in close succession, the Victoria and Central lines experience frequent acceleration and braking, contributing to heat buildup within the tunnels. I'm sure that this is probably one of those stupid suggestions that shows a lack of understanding of the problem, but could skipping stations help help this? Something like the following gets you 1/3rd less braking energy released into the tunnels: Station ABCDEFGH Train1 .. .. .. Train2 .. .. . Train3 . .. .. Taking a look at the peak time schedules they have trains coming every 2 minutes, so this seems like it would be reasonable for most people to have to sometimes wait 6 minutes for the right train, but generally not more than 4.

aldonius 1y ago
With frequent trains and close stop spacing you've plausibly got a situation where each train is entering and leaving each station at about the same time? So skip-stop might not save much acceleration/braking.
lmm 1y ago
Probably not, because the limiting factor on train throughput is remaining a safe braking distance behind the train in front. If the train in front of you has stopped at station D then you need to stop in station C even if you don't open the doors. (You could get around that by running the trains further apart, but that would be a critical loss of capacity).
- aeyes 1y ago
  There are some metro lines which use this skip-stop system, the distance between trains is created by staying longer in the station. https://en.wikipedia.org/wiki/Skip-stop https://en.wikipedia.org/wiki/Skip-stop
  - lmm 1y ago
    Right but the Victoria line puts a lot of effort into keeping station stop time to a minimum for the sake of capacity (it's the most intensive metro line in London, at 36-37tph, and one of the most intensive in the world). One way or another you have to space the trains out more to do skip-stopping.
Cthulhu_ 1y ago
I mean sure, less trains would help alleviate the problem (to simplify your proposal), but they still need to move all those people every day. Hence the 2020 reduction in heat increase, less people = less trains = less heat buildup.

by joshka 1y ago

aldonius 1y ago

With frequent trains and close stop spacing you've plausibly got a situation where each train is entering and leaving each station at about the same time? So skip-stop might not save much acceleration/braking.

lmm 1y ago

Probably not, because the limiting factor on train throughput is remaining a safe braking distance behind the train in front. If the train in front of you has stopped at station D then you need to stop in station C even if you don't open the doors. (You could get around that by running the trains further apart, but that would be a critical loss of capacity).

aeyes 1y ago
There are some metro lines which use this skip-stop system, the distance between trains is created by staying longer in the station. https://en.wikipedia.org/wiki/Skip-stop https://en.wikipedia.org/wiki/Skip-stop
- lmm 1y ago
  Right but the Victoria line puts a lot of effort into keeping station stop time to a minimum for the sake of capacity (it's the most intensive metro line in London, at 36-37tph, and one of the most intensive in the world). One way or another you have to space the trains out more to do skip-stopping.

Cthulhu_ 1y ago

I mean sure, less trains would help alleviate the problem (to simplify your proposal), but they still need to move all those people every day. Hence the 2020 reduction in heat increase, less people = less trains = less heat buildup.