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Nowadays, the train controller can stop a train remotely even if unable to raise the train on the radio. Still baffles me how packed the old system was with fa

by lb1lf 4y ago

Nowadays, the train controller can stop a train remotely even if unable to raise the train on the radio. Still baffles me how packed the old system was with failure modes, though.

NamTaf 4y ago
What system do they use for this? I’m not aware of any remote-stop functionality outside of driverless railways but that’s not to say it doesn’t exist.
- lb1lf 4y ago
  I only know what i've read about it in the papers, but I think the concept was that the trains and track are fitted with instrumentation enabling the train controller to see in real time exactly what segment of track any train is on at the moment; he will then periodically authorize a train to occupy the X next segments. Presumably the system is interlocked so that it is impossible to authorize two trains to occupy the same segment at the same time. If a train finds itself on a segment it has not been authorized for, it stops - regardless of what the driver thinks of the matter.
  - NamTaf 4y ago
    That system is track circuitry that uses relays to detect rolling stock when they short the two rails via their wheels. That exists widely, and it identifies that rolling stock is present in a track section. That same relay also locally (as in, on the ground at that location) triggers any signals to switch to red. Controllers can’t then give authorisation to another train to enter that section, nor can they override any red signal. In cases where it applies, they also can’t remotely control track switches to enter this occupied section. However there’s nothing with that system that then controls the rolling stock itself, so a driver can still SPAD if they don’t see or ignore the red, and the remote network controller absolutely cannot stop a train that is hurtling towards an occupied section. That’s all on the driver in the cab. Fun fact: track clips are used by track gangs to short these sections in lieu of a big axle sitting on it, which is one of the methods of providing site control to the gangs so trains don’t enter their worksite. It’s certainly not the only one, though.
    - lb1lf 4y ago
      I googled around a bit out of curiosity, and it appears the remote control is indirect - the train controller can override a green signal to red. (Presumably not the other way around!) All trains have instrumentation which will cause them to stop if they pass a red signal. The gritty details appear to be in the Togframføringsforskriften, however this has been repealed a couple of years ago, presumably to bring us in line with EU regulations - but I am too tired to try to figure this out tonight, though I have always been a sucker for figuring out how signalling systems work...
      - NamTaf 4y ago
        Yup, any controller can set a signal to red (that’s how we do track blocks, said clips are the backup to that because you always want the dude in the sky to know you’re there). Not all trains have kit to stop a SPAD, unless you meant specifically in the instance of the operator involved in this incident. Some do, but it’s absolutely not universal around the world. For example, Automatic Train Protection (ATP) can do this, but it requires both a track-side magnet and the rolling stock to have the kit for it. We use that to trigger our driver vigilance system acknowledgement when approaching suburban passenger stations. Failure to acknowledge the vigilance prompt will throw the brake to emergency and stop the train. That said, it’s absolutely not present out in the Wild West of freight (because maintaining that many ATP magnets is insanely prohibitive).
      - zidel 4y ago
        For information specific to Norway (in Norwegian) there is a lot here: https://trv.banenor.no/wiki/Forside https://trv.banenor.no/wiki/Forside https://www.jernbanekompetanse.no/wiki/Forside https://www.jernbanekompetanse.no/wiki/Forside

by lb1lf 4y ago

Nowadays, the train controller can stop a train remotely even if unable to raise the train on the radio. Still baffles me how packed the old system was with failure modes, though.

NamTaf 4y ago

What system do they use for this? I’m not aware of any remote-stop functionality outside of driverless railways but that’s not to say it doesn’t exist.

lb1lf 4y ago
I only know what i've read about it in the papers, but I think the concept was that the trains and track are fitted with instrumentation enabling the train controller to see in real time exactly what segment of track any train is on at the moment; he will then periodically authorize a train to occupy the X next segments. Presumably the system is interlocked so that it is impossible to authorize two trains to occupy the same segment at the same time. If a train finds itself on a segment it has not been authorized for, it stops - regardless of what the driver thinks of the matter.
- NamTaf 4y ago
  That system is track circuitry that uses relays to detect rolling stock when they short the two rails via their wheels. That exists widely, and it identifies that rolling stock is present in a track section. That same relay also locally (as in, on the ground at that location) triggers any signals to switch to red. Controllers can’t then give authorisation to another train to enter that section, nor can they override any red signal. In cases where it applies, they also can’t remotely control track switches to enter this occupied section. However there’s nothing with that system that then controls the rolling stock itself, so a driver can still SPAD if they don’t see or ignore the red, and the remote network controller absolutely cannot stop a train that is hurtling towards an occupied section. That’s all on the driver in the cab. Fun fact: track clips are used by track gangs to short these sections in lieu of a big axle sitting on it, which is one of the methods of providing site control to the gangs so trains don’t enter their worksite. It’s certainly not the only one, though.
  - lb1lf 4y ago
    I googled around a bit out of curiosity, and it appears the remote control is indirect - the train controller can override a green signal to red. (Presumably not the other way around!) All trains have instrumentation which will cause them to stop if they pass a red signal. The gritty details appear to be in the Togframføringsforskriften, however this has been repealed a couple of years ago, presumably to bring us in line with EU regulations - but I am too tired to try to figure this out tonight, though I have always been a sucker for figuring out how signalling systems work...
    - NamTaf 4y ago
      Yup, any controller can set a signal to red (that’s how we do track blocks, said clips are the backup to that because you always want the dude in the sky to know you’re there). Not all trains have kit to stop a SPAD, unless you meant specifically in the instance of the operator involved in this incident. Some do, but it’s absolutely not universal around the world. For example, Automatic Train Protection (ATP) can do this, but it requires both a track-side magnet and the rolling stock to have the kit for it. We use that to trigger our driver vigilance system acknowledgement when approaching suburban passenger stations. Failure to acknowledge the vigilance prompt will throw the brake to emergency and stop the train. That said, it’s absolutely not present out in the Wild West of freight (because maintaining that many ATP magnets is insanely prohibitive).
    - zidel 4y ago
      For information specific to Norway (in Norwegian) there is a lot here: https://trv.banenor.no/wiki/Forside https://trv.banenor.no/wiki/Forside https://www.jernbanekompetanse.no/wiki/Forside https://www.jernbanekompetanse.no/wiki/Forside