5 ms·

Acceleration signature depends on: - human driver - train capacity and current load - train model (or any powertrain variations) More reliable might be to c

by nuccy 2y ago

Acceleration signature depends on: - human driver - train capacity and current load - train model (or any powertrain variations) More reliable might be to check rail track features from accelerometer: tilt, turns, bumps, or a combinations of everything. Even sounds on turns, changes of backround during merging tunnels, etc. Integrated acceleration gives train speed, which is also useful along with other inputs.

modeless 2y ago
Yes, tilt, turns, and bumps are what I meant by accelerations, not just the train's forward acceleration.
- sakjur 2y ago
  If you’re not putting the phone on the floor, wouldn’t the person holding it introduce a randomness factor that would make it much harder to reliably measure those? And then there’s sun curves, packed leaves, ice and the cars’ suspension. I think I’d struggle with finding a signal through all that noise.
  - Normal_gaussian 2y ago
    Ive seen two seperate demos of doing this for the london underground based purely on the accelerometer. Accuracy is poor when blind, but if you have any info about where the user last had a location fix it became very good. Neither company found sufficient interest to deploy the sensor.
  - TeMPOraL 2y ago
    Contribution from the phone being held should be easy to cancel out for the most part, as high frequency noise. It of course gets much easier if you have acceleration data from two or more devices held by different people.
sofixa 2y ago
> human driver Not in any even remotely modern system that will have a high degree of automation and if there's a driver, they're only closing and opening doors, and telling the train to get going.
- AndrewSwift 2y ago
  I just took a one day initiation with the SNCF for driving trains in France. I assumed that everything would be automated but in fact nothing is. They explained that they regularly face situations that require human intervention (several times a day), and that even a little automation would reduce the level of attention on the part of the conductor. The conductor is required to interact with the controls at least every 30 seconds to avoid setting off alarms.
  - maeln 2y ago
    The SNCF is for regional and national train (with the exception of the RER) where the possibility of having a cow coming on the rail is non-negligible ... or a hot air ballon landing on the rail and stopping the Nantes-Paris lines for a whole morning :D . So I think it is a much, much harder environment to automate. Paris do have some metro line that are fully automatic (line 1 at least) and both Rennes metro lines are fully automatic. It is much easier to control the environment around a metro and ensure that nothing can go on the rails, and have surveillance system to check if, if it does happen, it is detected ASAP.
    - rossant 2y ago
      Paris metro lines 1, 4, and 14 are automatic at the moment.
    - sofixa 2y ago
      > The SNCF is for regional and national train (with the exception of the RER) where the possibility of having a cow coming on the rail is non-negligible ... or a hot air ballon landing on the rail and stopping the Nantes-Paris lines for a whole morning :D . Or camels: https://www.francetvinfo.fr/animaux/un-dromadaire-apercu-aux-bord-des-voies-pres-de-la-gare-de-melun_3149071.html https://www.francetvinfo.fr/animaux/un-dromadaire-apercu-aux... > So I think it is a much, much harder environment to automate. Paris do have some metro line that are fully automatic (line 1 at least) and both Rennes metro lines are fully automatic. It is much easier to control the environment around a metro and ensure that nothing can go on the rails, and have surveillance system to check if, if it does happen, it is detected ASAP. Even the non-fully automatic lines use heavy automation (e.g. lines such as 2, 3, 5, 7, 8, 9, 11, 12, 13).

by nuccy 2y ago

modeless 2y ago

Yes, tilt, turns, and bumps are what I meant by accelerations, not just the train's forward acceleration.

sakjur 2y ago
If you’re not putting the phone on the floor, wouldn’t the person holding it introduce a randomness factor that would make it much harder to reliably measure those? And then there’s sun curves, packed leaves, ice and the cars’ suspension. I think I’d struggle with finding a signal through all that noise.
- Normal_gaussian 2y ago
  Ive seen two seperate demos of doing this for the london underground based purely on the accelerometer. Accuracy is poor when blind, but if you have any info about where the user last had a location fix it became very good. Neither company found sufficient interest to deploy the sensor.
- TeMPOraL 2y ago
  Contribution from the phone being held should be easy to cancel out for the most part, as high frequency noise. It of course gets much easier if you have acceleration data from two or more devices held by different people.

sofixa 2y ago

> human driver Not in any even remotely modern system that will have a high degree of automation and if there's a driver, they're only closing and opening doors, and telling the train to get going.

AndrewSwift 2y ago
I just took a one day initiation with the SNCF for driving trains in France. I assumed that everything would be automated but in fact nothing is. They explained that they regularly face situations that require human intervention (several times a day), and that even a little automation would reduce the level of attention on the part of the conductor. The conductor is required to interact with the controls at least every 30 seconds to avoid setting off alarms.
- maeln 2y ago
  The SNCF is for regional and national train (with the exception of the RER) where the possibility of having a cow coming on the rail is non-negligible ... or a hot air ballon landing on the rail and stopping the Nantes-Paris lines for a whole morning :D . So I think it is a much, much harder environment to automate. Paris do have some metro line that are fully automatic (line 1 at least) and both Rennes metro lines are fully automatic. It is much easier to control the environment around a metro and ensure that nothing can go on the rails, and have surveillance system to check if, if it does happen, it is detected ASAP.
  - rossant 2y ago
    Paris metro lines 1, 4, and 14 are automatic at the moment.
  - sofixa 2y ago
    > The SNCF is for regional and national train (with the exception of the RER) where the possibility of having a cow coming on the rail is non-negligible ... or a hot air ballon landing on the rail and stopping the Nantes-Paris lines for a whole morning :D . Or camels: https://www.francetvinfo.fr/animaux/un-dromadaire-apercu-aux-bord-des-voies-pres-de-la-gare-de-melun_3149071.html https://www.francetvinfo.fr/animaux/un-dromadaire-apercu-aux... > So I think it is a much, much harder environment to automate. Paris do have some metro line that are fully automatic (line 1 at least) and both Rennes metro lines are fully automatic. It is much easier to control the environment around a metro and ensure that nothing can go on the rails, and have surveillance system to check if, if it does happen, it is detected ASAP. Even the non-fully automatic lines use heavy automation (e.g. lines such as 2, 3, 5, 7, 8, 9, 11, 12, 13).