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TLDR; There was a single train emitting both correct and erroneous signals. This caused trains in the vicinity to lose data link which triggered an emergency

TLDR; There was a single train emitting both correct and erroneous signals. This caused trains in the vicinity to lose data link which triggered an emergency brake safety feature. The article doesn't make clear what medium the trains communicate on which was affected (e.g. rail, wireless, powerline). They have not yet determined what caused the faulty hardware (or software???) on the faulty train to enter this state.

4ndr3vv 10y ago
Think you're looking at this story the wrong way; Its not about the fault but the bug hunting process. I propose: TL:DR - They had a strange hard to identify bug, but used a limited data set and interesting techniques to quickly find the esoteric cause of the problem.
- sweetjesus 10y ago
  imho his TL;DR is better than yours, but your improvements could be made to his. In my education we was taught that in science and business, the abstracts should tell the whole point of the story; the "spoiler" should not be saved till the end even though that makes for more fun; this is to allow a busy person to get the takeaway quickly and assess if they need to read all the detail. Whether anybody agrees with that or not, it's been burned into my way of looking at the world, so even when reading this article, all the way through I was gritting my teeth thinking "I wish I had some clue as to what I'm reading about." so to add in your point, to his TL;DR I would put in "the intial dataset included only the trains that had suffered the fault, but as the fault was caused by a functioning train, a more comprehensive dataset was necessary to find the problem; had it been provided initially, less detective work might have been necessary"
xobs 10y ago
The trains communicate wirelessly. The system is entirely underground, do theoretically interference shouldn't have been an issue. They shut off the mobile networks for a while to try and isolate the issue. It's interesting to read what was going on, though.
- noisy_boy 10y ago
  I'm not sure if you meant just the communication system was underground but some sections of the routes go overground (e.g. a large section of East West line is overground).
  - ppurka 10y ago
    This happened on the Yellow line, which is entirely underground.

4ndr3vv 10y ago

Think you're looking at this story the wrong way; Its not about the fault but the bug hunting process. I propose: TL:DR - They had a strange hard to identify bug, but used a limited data set and interesting techniques to quickly find the esoteric cause of the problem.

sweetjesus 10y ago
imho his TL;DR is better than yours, but your improvements could be made to his. In my education we was taught that in science and business, the abstracts should tell the whole point of the story; the "spoiler" should not be saved till the end even though that makes for more fun; this is to allow a busy person to get the takeaway quickly and assess if they need to read all the detail. Whether anybody agrees with that or not, it's been burned into my way of looking at the world, so even when reading this article, all the way through I was gritting my teeth thinking "I wish I had some clue as to what I'm reading about." so to add in your point, to his TL;DR I would put in "the intial dataset included only the trains that had suffered the fault, but as the fault was caused by a functioning train, a more comprehensive dataset was necessary to find the problem; had it been provided initially, less detective work might have been necessary"

xobs 10y ago

The trains communicate wirelessly. The system is entirely underground, do theoretically interference shouldn't have been an issue. They shut off the mobile networks for a while to try and isolate the issue. It's interesting to read what was going on, though.

noisy_boy 10y ago
I'm not sure if you meant just the communication system was underground but some sections of the routes go overground (e.g. a large section of East West line is overground).
- ppurka 10y ago
  This happened on the Yellow line, which is entirely underground.