Train doors require GPS signal to open despite stations being underground (2014) • Hacker News Board

Re: Train doors require GPS signal to open despite stations being underground (2014)

#61

Post by gkoz » Sat, Mar 14, 2015, 5:45 PM UTC

TazeTSchnitzel wrote: post #57

I can't believe HN is reacting to this as if checking location is a bad idea. It does have an emergency override. On the underground, particularly during rush hour, doors opening on the wrong side, or in the wrong place, could cause people to fall out of the train onto the tracks, in the dark, and risk serious injury or even death (especially with electrified rails). And using GPS and repeaters in the few spots where…

Adding a complex and unreliable dependency that has to be reimplemented underground and isn't really needed (because you don't need the GPS coordinates, just a little bit of local metadata)? Not ridiculous at all.

Re: Train doors require GPS signal to open despite stations being underground (2014)

#62

Post by sitkack » Sat, Mar 14, 2015, 5:47 PM UTC

TazeTSchnitzel wrote: post #57

I can't believe HN is reacting to this as if checking location is a bad idea. It does have an emergency override. On the underground, particularly during rush hour, doors opening on the wrong side, or in the wrong place, could cause people to fall out of the train onto the tracks, in the dark, and risk serious injury or even death (especially with electrified rails). And using GPS and repeaters in the few spots where…

Using an unauthenticated, jammable signal for a safety critical function is wrong, not something dictated by the practicality or expediency of the solution. It is absolutely wrong and stupid. Like Therac stupid.

And as someone mentioned below, there is already a solution for this exact problem; https://en.wikipedia.org/wiki/Balise

Re: Train doors require GPS signal to open despite stations being underground (2014)

#63

Post by [deleted] » Sat, Mar 14, 2015, 5:54 PM UTC

verytrivial wrote: post #41

I catch these trains every day. People are confused by the warning about a "slight delay" from the driver as we approach the stations. I occasionally say "GPS doors" and everyone who was previously confused instantly adopts a "seriously?!" face. I have NO idea how such a knuckle-headed design flaw can make it all the way through design and build with even minimally aware designers and engineers in charge.

[deleted]

Re: Train doors require GPS signal to open despite stations being underground (2014)

#64

Post by sitkack » Sat, Mar 14, 2015, 5:54 PM UTC

verytrivial wrote: post #41

I catch these trains every day. People are confused by the warning about a "slight delay" from the driver as we approach the stations. I occasionally say "GPS doors" and everyone who was previously confused instantly adopts a "seriously?!" face. I have NO idea how such a knuckle-headed design flaw can make it all the way through design and build with even minimally aware designers and engineers in charge.

Reinforces every stereotype I have about British Engineering(tm), precision watch gears cut with a hacksaw. 400 Hp steam powered lawn mowers. Jaguars.

Re: Train doors require GPS signal to open despite stations being underground (2014)

#65

Post by amelius » Sat, Mar 14, 2015, 6:02 PM UTC

TillE wrote: post #9

The only advantage GPS would have is that you don't have to install something (eg, a powered RFID tag) in each station. And yet, they've had to install "GPS repeater beacons" to work around this problem. Sounds like a typical case of bad design.

RFID tags don't necessarily need power.

And they can be quite cheap.

Re: Train doors require GPS signal to open despite stations being underground (2014)

#66

Post by pbhjpbhj » Sat, Mar 14, 2015, 6:12 PM UTC

sukilot wrote: post #31

sandworm wrote: post #17

So what happens in a power failure? I can see the need and advantage of a system to make sure that only the appropriate doors open at certain stations, but surely this could have been done with information at the local level. Barcodes, NFC, RFID ... to go with sats hundreds of miles in the sky augmented by repeaters is overly complex. Passengers are not cattle. I don't see why they cannot have local door control when…

Your claim needs evidence. A hypothetical murderer could open a door and push people out, no weapon necessary. In a fire, passengers could fall out a door onto third rail.

But are those risks less than the risk that in an emergency the doors can't be opened at all and the entire carriage of passengers are effected, eg burnt alive?

The old system of windows that slide down with a handle on the outside of the carriage seemed to work pretty well - hypothetically you could open the door and push people out or fall on the track. Wonder how many times that happened?

Re: Train doors require GPS signal to open despite stations being underground (2014)

#67

Post by joezydeco » Sat, Mar 14, 2015, 6:31 PM UTC

Just a reminder that stories like these are regularly accumulated and curated by the ACM's Committee on Computers and Public Policy, known as the RISKS Digest. In the pre-web days you might have remembered this as Usenet's comp.risks.

Peter G. Neumann has been moderating this publication online for almost 30 years now. Always interesting reading.

RISKS Digest: http://en.wikipedia.org/wiki/RISKS_Digest

Current Issue and Archives: http://catless.ncl.ac.uk/Risks/

1994 Book: http://www.amazon.com/Computer-Related-Risks-Peter-G-Neumann...

Re: Train doors require GPS signal to open despite stations being underground (2014)

#68

Post by maxerickson » Sat, Mar 14, 2015, 6:37 PM UTC

TazeTSchnitzel wrote: post #57

I can't believe HN is reacting to this as if checking location is a bad idea. It does have an emergency override. On the underground, particularly during rush hour, doors opening on the wrong side, or in the wrong place, could cause people to fall out of the train onto the tracks, in the dark, and risk serious injury or even death (especially with electrified rails). And using GPS and repeaters in the few spots where…

It's kind of hilarious that you kicked your post off with a glib denouncement of "HN" and then edited it to refer to information someone had posted prior to you making the comment.

It's also the case that most of the raspberries are aimed at the idea that it doesn't work very well, which is a failure regardless of the apparent reasonableness of the implementation.

Re: Train doors require GPS signal to open despite stations being underground (2014)

#69

Post by Someone » Sat, Mar 14, 2015, 7:04 PM UTC

TazeTSchnitzel wrote: post #59

Shivetya wrote: post #20

Earlier quoted context omitted.

surely there are restrictions opening while moving but while stopped seems a bit odd. Aren't they paying the driver to think, to know when to open or not open doors?

Reducing the amount the driver has to think reduces the potential for human error.

The potential, yes, but the risk of human error? Once you have reduced the amount of thinking the driver has to do, you start hiring drivers who aren't that good at thinking, and the ones that are good at it stop practicing it.

I don't have data showing it, but I think making the driver's work duller can make things less safe for his passengers.

Re: Train doors require GPS signal to open despite stations being underground (2014)

#70

Post by archagon » Sat, Mar 14, 2015, 7:45 PM UTC

sitkack wrote: post #64

verytrivial wrote: post #41

I catch these trains every day. People are confused by the warning about a "slight delay" from the driver as we approach the stations. I occasionally say "GPS doors" and everyone who was previously confused instantly adopts a "seriously?!" face. I have NO idea how such a knuckle-headed design flaw can make it all the way through design and build with even minimally aware designers and engineers in charge.

Reinforces every stereotype I have about British Engineering(tm), precision watch gears cut with a hacksaw. 400 Hp steam powered lawn mowers. Jaguars.

https://www.youtube.com/watch?v=1EBfxjSFAxQ&t=57