5 ms·

"the majority [of heat comes] from the train hitting the brakes as it pulls into the station, an intense friction that gives off an exorbitant amount of warm ai

"the majority [of heat comes] from the train hitting the brakes as it pulls into the station, an intense friction that gives off an exorbitant amount of warm air." I wonder if regenerative brakes can be installed (or are already installed...)

amarshall 8y ago
All of the newer “NTT” cars have regenerative braking[1]. NTT cars make up, as far as I can tell, the majority of current revenue-service rolling stock[2] (but there’s still a lot of older cars in-service). [1] http://web.mta.info/nyct/facts/ffenvironment.htm http://web.mta.info/nyct/facts/ffenvironment.htm [2] http://www.thejoekorner.com/carassignments/index.html http://www.thejoekorner.com/carassignments/index.html
adrianmonk 8y ago
And/or platform doors: https://en.wikipedia.org/wiki/Platform_screen_doors https://en.wikipedia.org/wiki/Platform_screen_doors Seems like they'd keep heat from the train from making its way onto the platform. And if platforms are air-conditioned, they'd keep that air from escaping into the tunnels. And of course they can also help with safety.
- bobthepanda 8y ago
  Doors only work if they can line up with every single train that services said platform. Unfortunately, not all trains share door positions, and most platforms will see a mixed fleet of trains. The new trains have consistent door positioning, but the old ones are still in good working order and aren't due for retirement until late 2020s-early 2030s.
  - manquer 8y ago
    It is still doable, you can start by splitting the running stock by similarly aligned doors run them on few line and start with the few lines which are now already aligned. Realistically by the time you are even close to half the 470 stations it will be late 2020's anyway. Then you can aim for full coverage as the stock is deprecated. It is more likely the $1-2 million per station cost is not high priority as say CBTC which will improve revenue as it increases capacity.
    - bobthepanda 8y ago
      The problem is that none of the lines except two of them are separated enough. Separating them to the degree required for this to work is not possible, because the crazy interlining is the only way to provide many trips in a patchwork system that was originally three competing subways; many transfers would not be available, and the remaining ones would not be able to handle the resulting transfer volume. It would also not be desirable, because right now reroutes are commonly used to maintain service in case of problems or maintenance; doors restricting fleets to lines would reduce operational flexibilty. The problem is also too large to segregate. We are talking about a third of the current fleet that is not compatible with new train door placements. Even after the oldest of these are retired with projected future train orders, it will be about a tenth of the fleet, larger than the entire Boston T rapid transit fleet.
  - adrianmonk 8y ago
    Maybe this could be solved by having platform doors that open in all the required positions? You could either add extra platform doors or make platform doors that are wider than the train doors and open part way to match the train. Unfortunately, if cars have different lengths, it increases permutations a lot. But you could handle even that by building a wall made entirely of doors (staggered on two door tracks), so the gap between any two doors can open up to any desired width.
ascorbic 8y ago
One neat, low techregenerative braking system used in some places is having the stations built slightly higher than the rest of the network. As the train comes into the station, the slope helps it slow down, and then when it leaves the station, the slope helps it accelerate. Never underestimate the energy stored by moving a fully laden train a few centimetres up.

amarshall 8y ago

All of the newer “NTT” cars have regenerative braking[1]. NTT cars make up, as far as I can tell, the majority of current revenue-service rolling stock[2] (but there’s still a lot of older cars in-service). [1] http://web.mta.info/nyct/facts/ffenvironment.htm http://web.mta.info/nyct/facts/ffenvironment.htm [2] http://www.thejoekorner.com/carassignments/index.html http://www.thejoekorner.com/carassignments/index.html

adrianmonk 8y ago

And/or platform doors: https://en.wikipedia.org/wiki/Platform_screen_doors https://en.wikipedia.org/wiki/Platform_screen_doors Seems like they'd keep heat from the train from making its way onto the platform. And if platforms are air-conditioned, they'd keep that air from escaping into the tunnels. And of course they can also help with safety.

bobthepanda 8y ago
Doors only work if they can line up with every single train that services said platform. Unfortunately, not all trains share door positions, and most platforms will see a mixed fleet of trains. The new trains have consistent door positioning, but the old ones are still in good working order and aren't due for retirement until late 2020s-early 2030s.
- manquer 8y ago
  It is still doable, you can start by splitting the running stock by similarly aligned doors run them on few line and start with the few lines which are now already aligned. Realistically by the time you are even close to half the 470 stations it will be late 2020's anyway. Then you can aim for full coverage as the stock is deprecated. It is more likely the $1-2 million per station cost is not high priority as say CBTC which will improve revenue as it increases capacity.
  - bobthepanda 8y ago
    The problem is that none of the lines except two of them are separated enough. Separating them to the degree required for this to work is not possible, because the crazy interlining is the only way to provide many trips in a patchwork system that was originally three competing subways; many transfers would not be available, and the remaining ones would not be able to handle the resulting transfer volume. It would also not be desirable, because right now reroutes are commonly used to maintain service in case of problems or maintenance; doors restricting fleets to lines would reduce operational flexibilty. The problem is also too large to segregate. We are talking about a third of the current fleet that is not compatible with new train door placements. Even after the oldest of these are retired with projected future train orders, it will be about a tenth of the fleet, larger than the entire Boston T rapid transit fleet.
- adrianmonk 8y ago
  Maybe this could be solved by having platform doors that open in all the required positions? You could either add extra platform doors or make platform doors that are wider than the train doors and open part way to match the train. Unfortunately, if cars have different lengths, it increases permutations a lot. But you could handle even that by building a wall made entirely of doors (staggered on two door tracks), so the gap between any two doors can open up to any desired width.

ascorbic 8y ago

One neat, low techregenerative braking system used in some places is having the stations built slightly higher than the rest of the network. As the train comes into the station, the slope helps it slow down, and then when it leaves the station, the slope helps it accelerate. Never underestimate the energy stored by moving a fully laden train a few centimetres up.