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Comment by popopobobobo | Hacker News Reader

I think MTA should also consider putting a barrier on the edge of the platform. So that we won't get dozens of people being pushed off to the rails.

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They look into it every few years but so far the costs to do so have been astronomical so it doesn't go past studies.

I don't have a good reference at the moment but from what I understand, most of it comes down to it being much harder to retrofit that kind of thing on to a 100+-year-old system than it is to build it into a new system. More specifically, since nothing was built with that in mind there are all kinds of challenges that would be very expensive to address like not all platforms are level or straight (imagine the cost and disruption involved in expanding and rebuilding the 4/5/6 platform and tunnels at Union Station to make them straight) and not all trains have doors that align in the same places (different generations of trains in service at the same time, different designs of trains on different lines, etc).

None of this means it can't or shouldn't be addressed eventually, but like many things in life there are reasons things aren't "just done" and it's important to understand those reasons if you want to make change happen.

6 people died from being struck by trains in a year (I think that was 2015 they pushed in their advertisements). There were about 1.76 billion rides in the same period.

As much as it's a feel-good measure, there is no conceivable way to justify the incredible expense of platform doors for such a small number of instances.

And the dirty secret is most of those are suicides. If they can't kill themselves on a train, they'll just go to the nearest bridge.

> If they can't kill themselves on a train, they'll just go to the nearest bridge.

This is a quibble in this context, but it's an important issue in others (such as access to guns):

Suicide is an impulsive act. The less "convenient" it is to kill oneself, the fewer suicides there are. A extra few minutes to reconsider can often be lifesaving.

This is well-researched (and still fun) podcast where I learned about this: https://gimletmedia.com/episode/guns/

> If they can't kill themselves on a train, they'll just go to the nearest bridge.

That's not true. Method substitution takes years.

In 2013 151 were struck and 53 died. Those are rather consistent numbers.

However, when you consider the millions that ride the Subway each day and the hundreds of millions each year it's a very small number.

Cars create more deaths per capita I believe.

Platform doors are not just for preventing falls onto the right of way, they also help to reduce litter, reduce delays due trains coming into stations slowly because of overcrowding and allow stations to be air conditioning.

Do you have a source for how often this happens? I can't find anything specifically about subway pushers in NYC. As far as I can tell, it's a very rare occurrence.

That being said, I see fairly high numbers of deaths in general, mainly attributed to suicides and alcohol/drug use.

How would this barrier work? Would it withdraw once the train pulled up or something?

There are gaps or doors that line up with the train doors when the subway stops

So this solution also requires operators able to stop the train at a particular point. Training is expensive!

Something like this maybe? http://philly.curbed.com/archives/2014/10/23/korean-company-...

I think it's crazy that the MTA hasn't already done this. Not only would it save a lot of lives, but it would also allow the platform to be climate controlled. You have no idea how many times I've sat there underground for 30+ minutes in sub-freezing or 100+ degree heat.

And the advertising potential on BOTH sides of the wall!

So we also have to pay for new HVAC systems on almost five hundred commercial buildings (that's what they are, even if underground) with no space for them? Cool.

Crazy is too strong a word because the costs involved would be astronomical / extraordinary / insane.

Platform doors are generally installed when you install modern signalling (CBTC) onto a line, which much of the NYC subway does not have. CBTC equipped trains can operate under Automatic Train Operation (ATO) meaning that trains can be made to always stop at the same location on the platform.

Furthermore, platform doors require you to have trains that have the doors in the same positions on the car body, which much of the newer subway fleet (R142,R188 & R143,R160,R179) has but the legacy fleet does not. This issue get compounded even more where multiple lines intersect (which is often due to the NYC subway's unique connectedness) requiring that certain stations would need to support 3 or 4 different car classes.

They investigated installing them here (Toronto) but the cost per station is pretty high, on the order of >$1M per platform. When you multiply that across a system as large as NYC that's easily half a billion dollars.

I'm not sure how many ads you have to sell to recoup the cost, but it's probably a lot.

...maybe kick Melania and Barron out of NYC?

edit - thought we were still talking about a simple low wall or gate, not the floor to ceiling glass in the GP post. leaving below for posterity..

> on the order of >$1M per platform

That's insanity! Over $1M for something every amusement park has for every ride? Lemme guess, these one have to be engineered to the point of 'impossible to fail' and installed by the employees of municipal cronies at 3x fair wages?

Talk about perfect being the enemy of good...

Insanity? That's dirt cheap. Think about how much mechanical complexity goes into each door, how it has multiple motors, servos, linear actuators and such. It has to be safe when closed, and it has to be safe when opened, it can't spontaneously shut in someone's face or pin them in the middle.

It needs multiple sensors that can handle being exposed to a lot of wear and tear. It needs to operate for years on end with, ideally, very little maintenance. It has to endure being buffeted by the forces of the train entering and leaving the station which exerts significant strain on any hinges or track mechanisms.

So you need a pair of these for each set of doors on the train, and if each car has three doors, and you have eight cars, that's 48 doors.

That leaves you with only $20,800 per door. You still need to build the walls themselves and you need to have this installed by the right technicians.

Do the math, don't bitch just because it sounds expensive.

Sorry, but $20K per door is still ridiculous. This is not new technology, automatically operated doors are used in many different settings. It's pure gov't waste to pay that much. It would be wasteful if it was 1/4 that much.

As an example that most automatic doors don't have to deal with, but is essential for railways:

The door must detect a 1-2cm obstruction (e.g. fingers, child's wrist) and be sufficiently weak that a child can pull their hand/wrist free. The door must not prevent a train from departing if only a hem of a skirt/trousers/coat is trapped. They must be strong enough to prevent anyone falling from the train while it is in motion, and must not be able to be forced open between stations.

Otherwise, approximately one person per year will die.

How much would you charge, to make doors to this specification?

And, some time in the next five years, an accident will happen, somewhere in the world. Your next door will need to prevent that situation, too.

[This is the situation in "wealthier" Europe, where it's pretty difficult to die on a train. Other countries may vary.]

The first part just means they need to have rubber padding. Still expensive since the design it's a one time job and can be reused for trains, trams, buses etc.

It's not that simple. Something different is required depending how the doors close (pneumatic, electric) and the expected use (high / low speed, crowded or not).

If the padding is too squashy, a trapped hand won't be detected and the person could be dragged under the train. Too sensitive, and someone leaning a suitcase on the door prevents the train from leaving.

It's a lot, but it's objectively not ridiculous.

You have no idea how much an elevator costs, do you?

It occurs to one that elevator doors are every bit as complex as what you ecan scribe and have been doing their job for over half a century at a cost of far less than that.

But really, you don't even need a door - a simple gate like on a ride at Disneyland, or heck even the gates at the station entrance would do nicely.

Not many elevators have 48 doors, and those that do cost a shit-ton more than a million dollars.

They seemed common in Japan when I visited:

https://alicegordenker.wordpress.com/2012/01/17/subway-safet...

(not my article)

There are numerous examples on the Tokyo Metro/Toei. The cheaper ones go up to about chest height and the more expensive ones completely block off the tracks by going up to the ceiling.

They also have the added benefit of showing people where to line up and make it harder for someone to cause the train to be late by rushing/holding the door

Anecdotally: last year I was riding in a train that hit someone who fell onto the tracks because the platform was so crowded. 30 minutes later, one station away, a woman lost both her legs when a train ran them over.

When I lived in Tokyo, they put platform guard walls in at many stations. They were about chest high and had sets of doors that would open before the train doors opened, and if we had them in NYC, both of those folks would have made it home without an incident.

In London, they simply close the station entrances (at street level) before it becomes so overcrowded. It can be a daily occurrence, e.g. at rush hour during a month of upgrade work on a particular line.

There is no record of anyone being killed or severely injured through overcrowding.

Jubilee also has station doors at new stations.

have you ever seen the tube system in London? it's a fully blocking barrier with a set of sliding doors that lines up precisely with the doors of the train cars when they pull in to the station.

that's probably the ideal solution, but not practical for New York because the system was never designed with precision stopping points on the platform in mind. there's a margin of error that is at least a meter or so in either direction right now.

Only on the newest part of the newest line, the Jubilee Line Extension. (1999? something like that.)

There are no "platform edge curtain" doors on other lines, even though many other lines also have computer controlled trains. (The "driver" is still there to press a button to start the train, but many lines almost drive themselves.) Although, even on the fully manual lines, the driver is expected to stop the train precisely -- the platforms aren't long enough for inaccuracy.

Only on new lines with straight platforms. Older ones are almost all on curves, a guy in the sliding doors business told me they looked into but the cost was too high as each station is on a different circumference bend so they would all be custom jobs.

The MTA is currently working on a solution that doesn't use barriers. [1] The short of it is that it will use thermal cameras and other sensors to determine if a human (and not a rat, for instance) has entered the tracks and is in danger.

It won't kill the trains but slow them down considerably and of course if it's a last second jumper or someone who falls right as the train is entering the station it won't work. But I imagine it will help solve a majority of the issues.

If you're nervous for your safety then I would recommend to stand on the far end of the platform where the front of the train stops at the station.

[1] http://www.nydailynews.com/new-york/mta-testing-systems-save...

There aren't dozens of people being pushed on the rails. Maybe in a two decade span probably but those barriers will never happen in NYC.

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