4 ms·

Why are deep stations expensive but tunnels cheap? I'd guess the opposite, tunnels being larger.

jltsiren 3y ago
In an urban subway line, stations may cover ~25% of the line. The platforms are long, while the distances between stations are often short. And while tunnels are standardized and their construction is largely automated, each station is a unique project that needs to be adapted to the specific location.
bluGill 3y ago
Because you need to dig out all that dirt, and this is normally done cut and cover. Even if you are only digging for stairs and elevators (building the station in the tunnel as Madrid does) that is a long way down. For shallow stations you can tell most people to walk down the stairs, but for deep stations nobody will so you have to build enough expensive elevators to handle everyone (and you still need the stairs for fire escape). Deep stations also mean people will be on the elevator longer so you need even more of them. (people may be running late so they need to load fast and it better not be long for the elevator to come when someone needs to get someplace)
- wolverine876 3y ago
  > elevators How are the elevators any more of a problem than in buildings, where they are commonplace, often for much taller structures (i.e., many more floors), and not considered a major expense? Edit: Thanks, good points about the volume/throughput.
  - throwaway22032 3y ago
    Metro stations have enormous throughput in comparison to a building.
  - steveBK123 3y ago
    A subway station needs to be able to handle, during rush hour, bursts of 100 people arriving every 2-3 minutes. A building generally does not. This is why even deep subway stations usually go with multiple levels of escalators to keep the flow of people moving continuously.
- kjkjadksj 3y ago
  Escalators usually carry more people if they are offered at least. Elevators get disgusting fast.
  - bluGill 3y ago
    For deep stations they don't work as well - you end up with a lot of switch backs.
    - kjkjadksj 3y ago
      Depends but you can have very long ones, too. In koreatown LA runs one of the longest escalators in the world down into the depths. Even the escalators at Universal Studios Hollywood have only a few landings and get you down an entire mountainside of vertical drop. I’d still take a switchback over cramming into what is basically a dumpster and urinal.
  - nradov 3y ago
    In the SF Bay Area, BART closed the station restrooms and so now homeless people and drunks use the elevators and escalators as toilets https://www.sfgate.com/bayarea/article/Rights-group-sues-BART-over-filthy-11052756.php https://www.sfgate.com/bayarea/article/Rights-group-sues-BAR...

In an urban subway line, stations may cover ~25% of the line. The platforms are long, while the distances between stations are often short. And while tunnels are standardized and their construction is largely automated, each station is a unique project that needs to be adapted to the specific location.

bluGill 3y ago

Because you need to dig out all that dirt, and this is normally done cut and cover. Even if you are only digging for stairs and elevators (building the station in the tunnel as Madrid does) that is a long way down. For shallow stations you can tell most people to walk down the stairs, but for deep stations nobody will so you have to build enough expensive elevators to handle everyone (and you still need the stairs for fire escape). Deep stations also mean people will be on the elevator longer so you need even more of them. (people may be running late so they need to load fast and it better not be long for the elevator to come when someone needs to get someplace)

wolverine876 3y ago
> elevators How are the elevators any more of a problem than in buildings, where they are commonplace, often for much taller structures (i.e., many more floors), and not considered a major expense? Edit: Thanks, good points about the volume/throughput.
- throwaway22032 3y ago
  Metro stations have enormous throughput in comparison to a building.
- steveBK123 3y ago
  A subway station needs to be able to handle, during rush hour, bursts of 100 people arriving every 2-3 minutes. A building generally does not. This is why even deep subway stations usually go with multiple levels of escalators to keep the flow of people moving continuously.
kjkjadksj 3y ago
Escalators usually carry more people if they are offered at least. Elevators get disgusting fast.
- bluGill 3y ago
  For deep stations they don't work as well - you end up with a lot of switch backs.
  - kjkjadksj 3y ago
    Depends but you can have very long ones, too. In koreatown LA runs one of the longest escalators in the world down into the depths. Even the escalators at Universal Studios Hollywood have only a few landings and get you down an entire mountainside of vertical drop. I’d still take a switchback over cramming into what is basically a dumpster and urinal.
- nradov 3y ago
  In the SF Bay Area, BART closed the station restrooms and so now homeless people and drunks use the elevators and escalators as toilets https://www.sfgate.com/bayarea/article/Rights-group-sues-BART-over-filthy-11052756.php https://www.sfgate.com/bayarea/article/Rights-group-sues-BAR...