5 ms·

Isn't this a security concern?

by merlingore 11y ago

graup 11y ago
According to the website, the location information isn't exact, but "calculated" (whatever that means).
- ff7c11 11y ago
  Ah. So no use in real-time if there is an unplanned delay as the map will show that the train just went past you when in fact it didn't. Shame.
  - Piskvorrr 11y ago
    Not really. As far as I understand the technologies (and I assume that Berlin does the same thing as every other city-user), a precise ("physical") GPS position is usually not reported (although newer systems do that as well), but a position at a "logical" map is. In case of buses, this usually means "left the previous stop at $xx:$yy, with $zz seconds of delay; reported average speed is normal for this area, so expected arrival is at $aa:$bb." In case of trains, the usual reported data is "has left section of track $AA, is now at $BB, delay $x seconds, expected at $CC in $yy:$zz". Not millisecond-perfect, but fairly precise to about a minute or two; the biggest guesstimate is the exact position (you'll see that all the trains seem to be using a single track, where in reality they would be on different ones). So, while delays are reported near-realtime (and thus the scenario you describe doesn't happen), the map might be inaccurate if the route needs to be changed (e.g. there's an accident blocking the road and a bus needs to take the next street instead). Again, with the rollout of GPS-equipment across fleets, this becomes less of an issue. Btw, most delays are unplanned ;)
    - Zach_the_Lizard 11y ago
      My understanding is that with newer CBTC signalling systems--not sure if Berlin is using that--the trains know pretty much exactly where they are on the track, along with the positions of all other trains, speeds, braking distance, etc. This allows the trains to run closer together than they could using fixed block signalling technology. It's not required for full automation, but it makes full automation relatively simple. The L train in New York is an example of where this is installed. My understanding is this means the two staff on the train are redundant; the driver pretty much just provides acknowledgement to the train to keep doing its thing, and the conductor only opens and closes doors and makes announcements (if that). They would run with only a single staff member except for union rules.
      - Piskvorrr 11y ago
        Oh, sure, there's all sorts of useful telemetry coming from the trains and the tracks, even with fixed-block signalling (unless you have a 100-year-old signalling infrastructure ;)). That's pretty much the case of most modern train systems: the driver is there essentially to (re)boot the train computers, push the "doors close" button, and for emergencies. Apart from that, the trains pretty much drive themselves (except when they don't, oh the joys of software). However, even when the position of the train is known precisely (no need for fancy CTBC, just start counting wheel revolutions from a known starting point and reset any measuring error at the next known-good point, usually a station - which is the basic way the Parisians do it with their driverless metro lines), not every transport agency exposes this sort of raw data to the general public; usually it's watered down to "it's between Station A and Station B, with X seconds of delay."
      - gsnedders 11y ago
        As far as I'm aware, all the Berlin S-Bahn and U-Bahn lines use absolute block signalling. FWIW, automation is actually mostly tangential to absolute v. moving block signalling. As far as I'm aware, most automated systems still use absolute block signalling.
      - ant6n 11y ago
        It seems that often the signalling system and the real time location reporting system aren't integrated. In NYC on many lines you get reports like 'there's a Brooklyn-bound train 2 stops away' that they make over the loud-speakers. Makes me wonder whether they have a separate device that just picks up when trains pass by a track segment, rather than using the information available via the signalling.
        Piskvorrr 11y ago
        Well, that's one of the most archaic systems out there: http://gothamist.com/2015/07/28/subway_steampunk_video.php http://gothamist.com/2015/07/28/subway_steampunk_video.php (Not the oldest, but using the oldest technology). If I understand it correctly, the only information available from the signalling system there is the rudimentary "there's something on this track segment now; it's up to the human controller to figure out what it is, where it came from and where it's headed."
- Kenp77 11y ago
  Yeah, that is a shame. Live data would be so much more useful!
- buster 11y ago
  It most likely means that there is no exact GPS data, but the company knows when trains arrive at a certain station and can calculate when the trains arrive at the next station (thus, they show us if a train or bus is late in minute-resolution). So it's easy to tell when a train is just departing, or when a train should be approximately 100 meters from the last station away, etc.
sveme 11y ago
In what way? You know, there are printed time tables hanging in all stations. They are even online, accessible from the middle east!
- Kenp77 11y ago
  Timetables can change, 'live' data does not. But, if it's 'calculated' then you're right, and it's pretty much a visual timetable. Also, I know you were joking, but let's not generalise and say middle east shall we? :)
  - sveme 11y ago
    Maybe I inferred too much from gp's comment and replied very tongue-in-cheek. Obviously I could have also said "accessible from Saxony (for the neo-nazis there), Cologne (for remnants of the red army faction) or Uganda (in case Josef Kony ever decides to turn up in Berlin)". Hope I now covered all major political and religious extremes. Back to the topic: Munich had something for the S-Bahn, the commuter train system, in their app for several years already. I really doubt that it's a security risk and find it sad that this is the first reaction something as nice as this gets.
    - merlingore 11y ago
      Haha, are you sure you covered all extremism there? I didn't mean it to come off so paranoid actually, I was just interested in starting a discussion about it, hence the "Isn't this" vs "THIS IS DEFINITELY"! I agree it's awesome tech, especially as it loads instantly on coffee shop internet, but all the comments here already reflect that.
  - deleted 11y ago
    [deleted]
ff7c11 11y ago
I thought the same. But I can't actually come up with a good reason. Maybe German trains are so punctual that you can infer their position anyway. Can someone in Berlin measure the lag? Next time I'm back there I might test it.
- _yy 11y ago
  > Maybe German trains are so punctual that you can infer their position anyway. That's what the map is doing, anyway (plus delays).
- pyvpx 11y ago
  I can only speak for Berlin and will say punctuality is not the strong point of S or U-bahn here.
  - odiroot 11y ago
    It's pretty good for underground U-Bahns and Stadtbahn. Ringbahn, Nord-Süd Bahn and overground U-Bahns are less reliable.
rmc 11y ago
If you're standing on the street, I'm sure you can see where the bus/trams etc are.
lagadu 11y ago
What? In my country every single station has a timetable saying which metro/train/bus stops there at exactly which minute. Are you suggesting we should randomize public transport schedules?
- ff7c11 11y ago
  Randomise the destinations as well. Will play havoc with the terrorists.
  - ckozlowski 11y ago
    Metro roulette! =D
  - hussong 11y ago
    Dark City comes to mind... John Murdoch: Excuse me. How do I get to the end of the line? Train Passenger: You want the Express. John Murdoch: [after train blows by him] Hey, how come that train didn't stop? Station Master: That's the Express.
    - superpatosainz 11y ago
      That sounds like the switchman by Juan Jose Arreola. Full text: http://www.jstor.org/stable/25293822 http://www.jstor.org/stable/25293822
DCoder 11y ago
Would that make https://www.flightradar24.com/ https://www.flightradar24.com/ a much bigger concern?
- gsnedders 11y ago
  The typical security concerns with rail networks don't really apply to aviation: it's much, much harder to stop a plane in flight (esp. at cruising altitude) than it is to stop a train.

Isn't this a security concern?

graup 11y ago

According to the website, the location information isn't exact, but "calculated" (whatever that means).

ff7c11 11y ago
Ah. So no use in real-time if there is an unplanned delay as the map will show that the train just went past you when in fact it didn't. Shame.
- Piskvorrr 11y ago
  Not really. As far as I understand the technologies (and I assume that Berlin does the same thing as every other city-user), a precise ("physical") GPS position is usually not reported (although newer systems do that as well), but a position at a "logical" map is. In case of buses, this usually means "left the previous stop at $xx:$yy, with $zz seconds of delay; reported average speed is normal for this area, so expected arrival is at $aa:$bb." In case of trains, the usual reported data is "has left section of track $AA, is now at $BB, delay $x seconds, expected at $CC in $yy:$zz". Not millisecond-perfect, but fairly precise to about a minute or two; the biggest guesstimate is the exact position (you'll see that all the trains seem to be using a single track, where in reality they would be on different ones). So, while delays are reported near-realtime (and thus the scenario you describe doesn't happen), the map might be inaccurate if the route needs to be changed (e.g. there's an accident blocking the road and a bus needs to take the next street instead). Again, with the rollout of GPS-equipment across fleets, this becomes less of an issue. Btw, most delays are unplanned ;)
  - Zach_the_Lizard 11y ago
    My understanding is that with newer CBTC signalling systems--not sure if Berlin is using that--the trains know pretty much exactly where they are on the track, along with the positions of all other trains, speeds, braking distance, etc. This allows the trains to run closer together than they could using fixed block signalling technology. It's not required for full automation, but it makes full automation relatively simple. The L train in New York is an example of where this is installed. My understanding is this means the two staff on the train are redundant; the driver pretty much just provides acknowledgement to the train to keep doing its thing, and the conductor only opens and closes doors and makes announcements (if that). They would run with only a single staff member except for union rules.
    - Piskvorrr 11y ago
      Oh, sure, there's all sorts of useful telemetry coming from the trains and the tracks, even with fixed-block signalling (unless you have a 100-year-old signalling infrastructure ;)). That's pretty much the case of most modern train systems: the driver is there essentially to (re)boot the train computers, push the "doors close" button, and for emergencies. Apart from that, the trains pretty much drive themselves (except when they don't, oh the joys of software). However, even when the position of the train is known precisely (no need for fancy CTBC, just start counting wheel revolutions from a known starting point and reset any measuring error at the next known-good point, usually a station - which is the basic way the Parisians do it with their driverless metro lines), not every transport agency exposes this sort of raw data to the general public; usually it's watered down to "it's between Station A and Station B, with X seconds of delay."
    - gsnedders 11y ago
      As far as I'm aware, all the Berlin S-Bahn and U-Bahn lines use absolute block signalling. FWIW, automation is actually mostly tangential to absolute v. moving block signalling. As far as I'm aware, most automated systems still use absolute block signalling.
    - ant6n 11y ago
      It seems that often the signalling system and the real time location reporting system aren't integrated. In NYC on many lines you get reports like 'there's a Brooklyn-bound train 2 stops away' that they make over the loud-speakers. Makes me wonder whether they have a separate device that just picks up when trains pass by a track segment, rather than using the information available via the signalling.
      - Piskvorrr 11y ago
        Well, that's one of the most archaic systems out there: http://gothamist.com/2015/07/28/subway_steampunk_video.php http://gothamist.com/2015/07/28/subway_steampunk_video.php (Not the oldest, but using the oldest technology). If I understand it correctly, the only information available from the signalling system there is the rudimentary "there's something on this track segment now; it's up to the human controller to figure out what it is, where it came from and where it's headed."
Kenp77 11y ago
Yeah, that is a shame. Live data would be so much more useful!
buster 11y ago
It most likely means that there is no exact GPS data, but the company knows when trains arrive at a certain station and can calculate when the trains arrive at the next station (thus, they show us if a train or bus is late in minute-resolution). So it's easy to tell when a train is just departing, or when a train should be approximately 100 meters from the last station away, etc.

sveme 11y ago

In what way? You know, there are printed time tables hanging in all stations. They are even online, accessible from the middle east!

Kenp77 11y ago
Timetables can change, 'live' data does not. But, if it's 'calculated' then you're right, and it's pretty much a visual timetable. Also, I know you were joking, but let's not generalise and say middle east shall we? :)
- sveme 11y ago
  Maybe I inferred too much from gp's comment and replied very tongue-in-cheek. Obviously I could have also said "accessible from Saxony (for the neo-nazis there), Cologne (for remnants of the red army faction) or Uganda (in case Josef Kony ever decides to turn up in Berlin)". Hope I now covered all major political and religious extremes. Back to the topic: Munich had something for the S-Bahn, the commuter train system, in their app for several years already. I really doubt that it's a security risk and find it sad that this is the first reaction something as nice as this gets.
  - merlingore 11y ago
    Haha, are you sure you covered all extremism there? I didn't mean it to come off so paranoid actually, I was just interested in starting a discussion about it, hence the "Isn't this" vs "THIS IS DEFINITELY"! I agree it's awesome tech, especially as it loads instantly on coffee shop internet, but all the comments here already reflect that.
- deleted 11y ago
  [deleted]

ff7c11 11y ago

I thought the same. But I can't actually come up with a good reason. Maybe German trains are so punctual that you can infer their position anyway. Can someone in Berlin measure the lag? Next time I'm back there I might test it.

_yy 11y ago
> Maybe German trains are so punctual that you can infer their position anyway. That's what the map is doing, anyway (plus delays).
pyvpx 11y ago
I can only speak for Berlin and will say punctuality is not the strong point of S or U-bahn here.
- odiroot 11y ago
  It's pretty good for underground U-Bahns and Stadtbahn. Ringbahn, Nord-Süd Bahn and overground U-Bahns are less reliable.

rmc 11y ago

If you're standing on the street, I'm sure you can see where the bus/trams etc are.

lagadu 11y ago

What? In my country every single station has a timetable saying which metro/train/bus stops there at exactly which minute. Are you suggesting we should randomize public transport schedules?

ff7c11 11y ago
Randomise the destinations as well. Will play havoc with the terrorists.
- ckozlowski 11y ago
  Metro roulette! =D
- hussong 11y ago
  Dark City comes to mind... John Murdoch: Excuse me. How do I get to the end of the line? Train Passenger: You want the Express. John Murdoch: [after train blows by him] Hey, how come that train didn't stop? Station Master: That's the Express.
  - superpatosainz 11y ago
    That sounds like the switchman by Juan Jose Arreola. Full text: http://www.jstor.org/stable/25293822 http://www.jstor.org/stable/25293822

DCoder 11y ago

Would that make https://www.flightradar24.com/ https://www.flightradar24.com/ a much bigger concern?

gsnedders 11y ago
The typical security concerns with rail networks don't really apply to aviation: it's much, much harder to stop a plane in flight (esp. at cruising altitude) than it is to stop a train.