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Old July 31st, 2013, 01:29 PM   #521
Pansori
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Quote:
Originally Posted by VECTROTALENZIS View Post
I think those extra seconds is necessary for safety. It's very often that the doors close and almost have a leg or hand or head still in between. Even the body can be between the metro carriage's doors and the security doors, like squeezed in between. Since it's crowded you almost get squeezed into that dead zone everytime. Image if the train would just leave if you some body partstill outside...

There has been several cases a couple of years ago people getting killed and even getting their heads chopped off...

Safety is better than getting that 5 mins earlier to work...
Yet again, does this not apply to other metro systems elsewhere? There are very crowded systems in many cities using similar technology, rolling stock and station layout.

AND I'm sure there are automated ways (such as infrared sensors) of ensuring that there are no people in between train and platform doors. And even if there is someone stuck how can one person standing at the front of the train tell? He simply couldn't see that without physically checking every door.

Therefore I just don't see how exactly that would make sense.
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Old July 31st, 2013, 02:05 PM   #522
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Yes there are ways to check for people between the PSD and train door. You have probably noticed the lights at the end of the platform. Also CCTV and I would guess systems that would prevent departure if the doors are not in a locked position. But still, that doesn't explain the long dwell time.
Is there a dwell time before opening the doors also?

I would put my money on saiho's explanation. That's the only one making sense to me.
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Old July 31st, 2013, 02:53 PM   #523
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Yes there are ways to check for people between the PSD and train door. You have probably noticed the lights at the end of the platform. Also CCTV and I would guess systems that would prevent departure if the doors are not in a locked position. But still, that doesn't explain the long dwell time.


I would put my money on saiho's explanation. That's the only one making sense to me.
That's right. Current technology is fully sufficient to prevent someone from getting stuck between the platform and train doors. It's not even a rocket science but rather basic movement/infrared sensors or something similar that you can get in any electronic hardware shop. So that one doesn't sound like a valid reason.

And which part of Saiho's explanation do you mean? Schedule? Most probably not. But safety overdrive might be it. Still I just wonder how exactly does it work? What exactly are they doing to take those extra 4-5 seconds? Maybe there is some additional automated system that takes the time which is not used (or just switched off) in other systems? I'm just curious to know because there MUST be an EXACT reason (or multiple reasons) for that. Even if they just do nothing for those 5 seconds. Maybe there is a H&S regulation saying "do not move the train for at least 7 seconds after doors are closed and safety systems show full clearance". Even if this is the case it would be good to know because otherwise I'll start having nightmares at night where I'll be stuck in a metro car which never departs from its station.

Quote:
Is there a dwell time before opening the doors also?
There is but it's considerably shorter. Maybe 2-2.5 seconds. Pretty much in line with other systems that I have seen except some European systems (Paris, London, maybe some others) which use different rolling stock and are considerably older and different in many ways.

In London Underground, for instance, they sometimes start opening doors even before the train has come to a halt (does not apply to Jubilee line which has platform doors in some stations. It has longer dwelling times than other lines but still not nearly as long as in Chinese cities and are more comparable to the likes of Singapore or Hong Kong). Dwell time in London before departure is also quite often no longer than 1 second. I'm critical of London transport in general but one thing I can't complain about is dwell times with door openings/closures against train stopping/departing. They really push it to the limit sometimes.

But like I said I would not even compare Chinese systems to most European systems because they tend to be quite different in many ways. However it's fair to compare to systems that are more comparable in age, layout and rolling stock which would be other systems in Asia such as Hong Kong, Singapore, Bangkok. I wonder how it is in Tokyo?

Last edited by Pansori; July 31st, 2013 at 02:59 PM.
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Old July 31st, 2013, 04:13 PM   #524
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Quote:
Originally Posted by Pansori View Post
Excessive safety measures sound like the most likely reason but is it really necessary? I mean there are all kinds of sensors and safety systems which ensure that things work properly. And most stations have platform doors anyway so as long as all doors are shut there should be absolutely no reason to take additional visual checks. It's just that I fail to make sense of it.
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Originally Posted by Pansori View Post
That's right. Current technology is fully sufficient to prevent someone from getting stuck between the platform and train doors. It's not even a rocket science but rather basic movement/infrared sensors or something similar that you can get in any electronic hardware shop. So that one doesn't sound like a valid reason.
The issue is not the hardware but the software (literally and metaphorically) I think the Chinese have taken platform screen doors / gates for granted (they are installed in 90% of all stations in china) so they start using them like this: @41 seconds



The deaths and injuries caused by PSDs are caused by this behavior. Should something happen the sensor could have failed or the driver didn't notice the alert or something. This is China we're talking about, something usually slips through the cracks when you build like 4 subway lines simultaneously. On the same vein the safety software and culture in management is probably not well implemented ATM. So management adopted a go slow and check everything approach which might be less efficient but it's less risky.

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Originally Posted by Pansori View Post
And which part of Saiho's explanation do you mean? Schedule? Most probably not. But safety overdrive might be it. Still I just wonder how exactly does it work? What exactly are they doing to take those extra 4-5 seconds? Maybe there is some additional automated system that takes the time which is not used (or just switched off) in other systems? I'm just curious to know because there MUST be an EXACT reason (or multiple reasons) for that. Even if they just do nothing for those 5 seconds. Maybe there is a H&S regulation saying "do not move the train for at least 7 seconds after doors are closed and safety systems show full clearance". Even if this is the case it would be good to know because otherwise I'll start having nightmares at night where I'll be stuck in a metro car which never departs from its station.
The loose schedule is probably a safety feature to put less emphasis on speed and stress on drivers. If they didn't China would have an Amagasaki rail crash every week. You know the Chinese are all about speed. The culture of speed and efficiency is quite easy to develop but the culture of safety takes more time. Also have huge dwells times "padded" into your schedule is a quick and sneaky way of fudging your punctuality stats.
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Old July 31st, 2013, 04:43 PM   #525
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I totally agree with Pansori. And then, I would add quite a great time of dwell BEFORE the doors open, not only after. In Hong Kong that doesn't exist yet the trains are much much longer.

I don't know for sure but it seems to me the button of opening/closing the doors is AT the station, and not in the driver's cab.
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Old July 31st, 2013, 06:44 PM   #526
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Quote:
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And the delay occurs during rush hours too so I don't think this is the reason anyway.
Ahh, if it also happens during rush hour, then it's probably not sticking to schedule.
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Old July 31st, 2013, 07:06 PM   #527
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You can't trust the sensors in the doors in cities like Guangzhou or Shenzhen. People seriously rip the doors open, or hold them back to allow themselves to squeeze in or out of the train. Nearly everytime I ride in rush hour I see a few body parts stuck in between. Yes, if the sensors work properly, it will catch these problems, but I've seen doors ripped off their hinges before by crazy old people, and what if the sensor was ripped out and failed to activate? You can't trust any advanced technology with the Chinese Mainlanders who don't care about anyone or anything but themselves and their own property. In Hong Kong, people are much more patient and polite, and don't do any of the crazy things I see everyday on the GZ Metro. The delay is absolutely a must, without it there would surely be a major incident if the driver didn't do a visual check before hopping back in the train. I don't think you spent enough time here to fully understand the importance of the safety checks in the Mainland metro systems.
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Old July 31st, 2013, 07:14 PM   #528
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Quote:
Originally Posted by Northridge View Post
Yes there are ways to check for people between the PSD and train door. You have probably noticed the lights at the end of the platform. Also CCTV and I would guess systems that would prevent departure if the doors are not in a locked position. But still, that doesn't explain the long dwell time.
Is there a dwell time before opening the doors also?

I would put my money on saiho's explanation. That's the only one making sense to me.
Shanghai and Guangzhou both have metro safety observers posted along the platform, they will signal the driver when all doors are secure, only then the driver can board the train and start driving.
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Old July 31st, 2013, 08:01 PM   #529
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Quote:
Originally Posted by Pansori View Post
And which part of Saiho's explanation do you mean? Schedule?
Mainly "safety overdrive". I'm also under the impression that things take a little bit longer in China and patience is something you need while traveling in that country.

Quote:
Originally Posted by Pansori View Post
There is but it's considerably shorter. Maybe 2-2.5 seconds. Pretty much in line with other systems that I have seen except some European systems (Paris, London, maybe some others) which use different rolling stock and are considerably older and different in many ways.
I experienced that the dwell time was longer in Shanghai, so I guess the procedures are a bit different.

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Originally Posted by Pansori View Post
But like I said I would not even compare Chinese systems to most European systems because they tend to be quite different in many ways. However it's fair to compare to systems that are more comparable in age, layout and rolling stock which would be other systems in Asia such as Hong Kong, Singapore, Bangkok. I wonder how it is in Tokyo?
For Tokyo, the dwell time are not as long. It is what you would expect.
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Old July 31st, 2013, 09:10 PM   #530
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Quote:
Originally Posted by hmmwv View Post

Shanghai and Guangzhou both have metro safety observers posted along the platform, they will signal the driver when all doors are secure, only then the driver can board the train and start driving.
Ok, so this might be it: even AFTER all the doors are closed the driver has to get a separate signal from the station staff to get back in and operate the train. Could that be it? Would make perfect sense. Just what about Shenzhen? I'm pretty sure they have at least one or two people at the platforms even though I never paid attention if they communicate with the driver.
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Old July 31st, 2013, 09:17 PM   #531
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they want to avoid this

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Old July 31st, 2013, 09:30 PM   #532
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Yes. The question is if the long dwell times is required to avoid those situations. Clearly they can't hurt from a safety perspective, but they can/do delay and make journeys take longer time.
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Old August 1st, 2013, 01:28 AM   #533
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This is a clear indication to put platform screen doors. Security should be the first priority. Even just a half height screen door, if cost is a concern would be sufficient enough.
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Old August 1st, 2013, 09:09 AM   #534
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Just to be clear, the video description says it's in Korea.
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Old August 2nd, 2013, 12:35 AM   #535
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Quote:
Originally Posted by Pansori View Post
Ok, so this might be it: even AFTER all the doors are closed the driver has to get a separate signal from the station staff to get back in and operate the train. Could that be it? Would make perfect sense. Just what about Shenzhen? I'm pretty sure they have at least one or two people at the platforms even though I never paid attention if they communicate with the driver.
Yes, those guys watch the PSDs close, making sure no one is stuck between the carriage and the doors, signal the driver, who then gets in the cab and start the train.

Quote:
Originally Posted by silent_dragon View Post

This is a clear indication to put platform screen doors. Security should be the first priority. Even just a half height screen door, if cost is a concern would be sufficient enough.
Safety observers are posted even at stations with PSDs.
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Old August 12th, 2013, 08:18 AM   #536
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August 8th 2013

Xili Station starts construction

Xili station is the transition hub of Line 5/7/15.



by 深圳地铁集团
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Old August 12th, 2013, 04:36 PM   #537
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Just to be clear, the video description says it's in Korea.
Really? I thought Koreans mostly use hangul these days in their metro systems particularly rather than hanja, but the exit sign is clearly in Chinese or Japanese: 出口. Always possible for it to be multilingual though. Korea seems to be quite good at that.
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Old August 12th, 2013, 04:50 PM   #538
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First day of the closure of Huaqiang North Road for the following 36 months for the construction of Xili line

may I make an off topic comment?
there is a burger king in shenzhen....
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Old August 12th, 2013, 05:04 PM   #539
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I wonder how many lanes were there before the construction started. The road looks so wide!!
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Old August 12th, 2013, 05:44 PM   #540
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may I make an off topic comment?
there is a burger king in shenzhen....
Why? Burger King is a pretty popular fast food restaurant world wide
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