

A suggestion to MikeBloomberg: Preventing the next murder on the 7 train   - ajayjapan
http://ajayjapan.tumblr.com/post/39194119362/a-suggestion-to-mikebloomberg-preventing-the-next

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snogglethorpe
This has, of course, been suggested about 37 billion times (judging from the
blogs/forums I read...).

It's not a bad idea in the abstract, but it's also not a trivial and cheap
project. The author's example of Japan leaves out the little fact that
although it's used on some new lines, and is being retrofitted on some old
ones, the _vast_ majority of Japanese rail/subway lines do not use platform
barriers, and it will certainly be many decades, if ever, before a significant
number do.

Besides the obvious construction costs, to make platform barriers work you
need very consistent door positioning, which is maybe not so hard for new
systems, but is a much bigger problem for old systems like the NYC subway
(with multiple types of running stock, etc).

NYC has the additional problem that it has _much_ higher (up to an order of
magnitude in some cases) construction costs for public works projects than
most other countries.

On the positive, platform doors are not an "all or nothing" proposition ...
they can be added line-by-line, or station-by-station, as soon as necessary
conditions are in place.

Certainly it's not a bad idea to study for the future, but it's also certainly
not a simple project to undertake, and even if started soon, it would be a
long time before enough any significant portion of the system is protected.

~~~
mithaler
I happen to live on the 7 train, so I know a fair bit about the difficulties
of installing it there.

The 7 train is still controlled entirely manually, with the old block-based
signalling mechanism that can only be aware of the location of a train in very
vague terms. It's currently having CBTC (Communications-Based Train
Control)[0] installed, which will give dispatchers much higher resolution
information about the location of every train, and go a very long way towards
automating the entire system. CBTC installation is scheduled to be completed
in 2016, and it's the reason why there are currently so many service
disruptions afflicting it during weekends (it actually just began a series of
13 consecutive weekends during which it will not go into Manhattan). If I
recall correctly from the posters, the total budget of the project is about
$750 million.

If and when the line is fully automated someday, it will become possible to
create a reliable barrier mechanism (like what currently exists on the very
small automated portions of the NYC subway, which is really just the JFK
AirTrain). Until then, human operators can't reliably get the train cars to
stop in the same place.

[0] [http://en.wikipedia.org/wiki/Communications-
based_train_cont...](http://en.wikipedia.org/wiki/Communications-
based_train_control)

~~~
snogglethorpe
> _If and when the line is fully automated someday... Until then, human
> operators can't reliably get the train cars to stop in the same place._

Note that it certainly _is_ possible to consistently do very accurate stops
with only unassisted human operators; Japanese rail operators have done this
as a matter of course, AFAIK using simple visual alignment aids, for as long
as I can remember. [Traditionally it's done because people are lined up at the
door locations (marked on the platforms), not for platform barriers.]

It's more a matter of operating culture and training than technology.

[Of course changing the latter may be easier in NYC!]

------
greenyoda
_"On average 200 people lose their lives on the New York City subway, a year.
Surely the cost of erecting these barriers is worth less than those souls
lost."_

This doesn't sound right. I live in NYC, and people getting killed by trains
is generally a newsworthy event. It's not something that one hears about every
couple of days, as would be the case if it happened to 200 people every year.
Also, for the fraction of these deaths that are suicides (which probably far
exceed the number of people being deliberately pushed), building barriers on
the platforms will not save these people's lives, since there are many
alternate ways of committing suicide.

The NYC subway has 468 stations[1], with the larger ones (e.g., Times Square)
having a dozen or more platforms. Add to that the commuter rail lines (e.g.,
LIRR, PATH, Metro North) and you have even more (Penn Station and Grand
Central are huge). It would probably cost billions of dollars to build gates
on every platform. These billions of dollars could probably save many more
than 200 lives a year if, for example, they were spent on improving the health
of poor children in NYC. (But in any case, the city doesn't have billions of
extra dollars lying around.)

[1] <https://en.wikipedia.org/wiki/New_York_City_Subway>

------
pacovell
Looking at the trains, they have no bumper and are sure to chew up anything in
their path. Couldn't we design and build some kind of tough, inflatable bumper
and install for a reasonable price?

Yes, you would get badly banged up (watch the 3rd rail!) but would probably
stand a better chance. I'd also like to verify the average actual cause of
death before fully backing this idea.

------
GLStephen
They could also have the train slow down prior to the station and then enter
into the station at a speed a person can outrun.

~~~
lexande
This would waste something like 250 million person-hours (or about 350
lifetimes) of riders' time every year, more than the total number of annual
deaths. It would also add to operating costs and decrease capacity on
overcrowded lines.

------
jannorthoff
That reminds me of my surprise when I went to Taiwan and saw similar barriers
in every metro station. Even without crazy people, it's really nice to have
when children are around.

