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> It's a fundamentally advisory system Couldn't the train's computer simply advise the engineer (that's the guy controlling the train correct?) to slow the hel

> It's a fundamentally advisory system Couldn't the train's computer simply advise the engineer (that's the guy controlling the train correct?) to slow the hell down when traveling too fast in a particular zone? Would that not be a step in the right direction? Maybe the system could even require that the engineer dismiss the warning by actually applying the brakes. Maybe after that doesn't happen the train can apply the brakes for you. That doesn't seem that complicated. I'm not trying to be argumentative. I'd love to hear some specifics about what complexity that adds.

deleted 11y ago
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rayiner 11y ago
How does the train know where it is? Remember, Amtrak runs some locomotives that are decades old. It's not like there is a "train's computer" equipped with GPS to know where it is.
- Symbiote 11y ago
  Steam trains in Europe¹ — used for tourism etc — are retrofitted with the necessary safety equipment. Otherwise they aren't allowed on normal railways, and will be restricted to running at low speed on entirely private lines. The train doesn't strictly need to know where it is — just what the maximum speed at that location is. Electronic pulses through the rails are one option, or transmitters at speed limit changes; presumably there are other ways too. ¹ The parts with safe trains, anyway.
- sparky_z 11y ago
  Well the GPS would be the part you add during the retrofit. It's not like they're that expensive anymore. Like someone1234 was saying, this seems like a problem that could be solved (at least as a prototype) by a smartphone app with a database of speed limits. Where's the complexity that makes that unfeasible?
- CamperBob2 11y ago
  There's this thing called GPS. It would cost about $100 to have the train "know" where it is. I don't understand this argument at all. Why are humans even in this particular loop? It's a train, not a car or an aircraft! It's not going anywhere it didn't go before, and it has no business going 1 MPH faster or slower past any given point on the track than it did the last time! You could implement a half-dozen fail-safe redundant controls for less than what it takes to pay an engineer to sit there and do a robot's job poorly.
  - jcrawfordor 11y ago
    GPS, especially inexpensive GPS, is widely considered unsuitable for life-safety applications, for a variety of reasons. The bottom line is that it is not accurate or reliable enough. This is why all commercial uses of GPS have a backup mechanism of some sort, and indeed most navigation is far less reliant on GPS than people believe (e.g. airplanes continue to make extensive use of VOR and ILS). Ships at sea are perhaps the only environment in which satellite positioning is sometimes relied on exclusively, and of course as soon as they are near any other object (land, another ship) they rely on visual navigation for safety. The problem with the rail network is figuring out this backup system.
    - CamperBob2 11y ago
      GPS, especially inexpensive GPS, is widely considered unsuitable for life-safety applications, for a variety of reasons. And unaided humans are perfect. Got it. The problem with the rail network is figuring out this backup system. Well, considering there's no backup system in place on many routes now, I'd say even the flakiest iPhone speed-alarm app is better than nothing. I can program my car to tell me if I exceed the speed limit. I'm sure multiple people will chime in to tell me several very good reasons why trains can't do that (or downmod me for asking.) In this case it might not have been enough to save the train, though, if the speculation is correct about the engineer being temporarily knocked out due to hitting his head while ducking a rock that might or might not have been chucked through the windshield. Wow, it's 2016 and I just typed that. I feel like I fell down a rabbit hole that leads straight to the 1890s.
- Animats 11y ago
  Usually, by communicating with RFID devices that sit between the rails. Most of these require no external power or connections; they just report their location. Some have connections to the signal system and report the status of signals and switches ahead. The ruggedness required of railroad lineside components is very high. They have to resist rain, snow, ice, flooding, hurricanes, vandalism, snowplows, and the machine that replaces the track ballast.[1] There's no reason the Northeast Corridor shouldn't have had PTC years ago, though. That's a busy line, and since it's electrified it has lots of wayside equipment already. There's resistance from the American Association of Railroads about equipping long freight lines out west and in the south, some of which don't have much traffic. That doesn't apply to the Northeast Corridor. Speed limit enforcement isn't new to railroading. Many subway systems, including NYC's, have had it for many decades. It's crude, based on timers between signals, but it works. Subways tend to have so many short signal blocks that block-based speed control works reasonably well. Above-ground lines have much longer blocks. Freight rail in open country can go miles between signals. [1] https://www.youtube.com/watch?v=UbfCX3WRL7g https://www.youtube.com/watch?v=UbfCX3WRL7g
NamTaf 11y ago
Driving a train, with multiple connected bodies together, is a fair whack different to driving a car. You have to forecast your decisions a lot more lest you introduce some nasty dynamics that can absolutely cause derailment (i.e.: excessive run-in) if extremely bad. Secondly, the approach that rail takes all over the world is to have highly interlocked fail-safe systems. Refer to safety integrity levels. [1] Track permission systems operate at SIL 4. It's EXTREMELY hard to 'write an app' that starts ticking the SIL boxes. The GEs of the world sink an incredible amount of money into automating train control and train driving. Still, it comes slowly because of the sheer complexity of hammering out every single corner case. [1]: https://en.wikipedia.org/wiki/Safety_integrity_level https://en.wikipedia.org/wiki/Safety_integrity_level

deleted 11y ago

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rayiner 11y ago

How does the train know where it is? Remember, Amtrak runs some locomotives that are decades old. It's not like there is a "train's computer" equipped with GPS to know where it is.

Symbiote 11y ago
Steam trains in Europe¹ — used for tourism etc — are retrofitted with the necessary safety equipment. Otherwise they aren't allowed on normal railways, and will be restricted to running at low speed on entirely private lines. The train doesn't strictly need to know where it is — just what the maximum speed at that location is. Electronic pulses through the rails are one option, or transmitters at speed limit changes; presumably there are other ways too. ¹ The parts with safe trains, anyway.
sparky_z 11y ago
Well the GPS would be the part you add during the retrofit. It's not like they're that expensive anymore. Like someone1234 was saying, this seems like a problem that could be solved (at least as a prototype) by a smartphone app with a database of speed limits. Where's the complexity that makes that unfeasible?
CamperBob2 11y ago
There's this thing called GPS. It would cost about $100 to have the train "know" where it is. I don't understand this argument at all. Why are humans even in this particular loop? It's a train, not a car or an aircraft! It's not going anywhere it didn't go before, and it has no business going 1 MPH faster or slower past any given point on the track than it did the last time! You could implement a half-dozen fail-safe redundant controls for less than what it takes to pay an engineer to sit there and do a robot's job poorly.
- jcrawfordor 11y ago
  GPS, especially inexpensive GPS, is widely considered unsuitable for life-safety applications, for a variety of reasons. The bottom line is that it is not accurate or reliable enough. This is why all commercial uses of GPS have a backup mechanism of some sort, and indeed most navigation is far less reliant on GPS than people believe (e.g. airplanes continue to make extensive use of VOR and ILS). Ships at sea are perhaps the only environment in which satellite positioning is sometimes relied on exclusively, and of course as soon as they are near any other object (land, another ship) they rely on visual navigation for safety. The problem with the rail network is figuring out this backup system.
  - CamperBob2 11y ago
    GPS, especially inexpensive GPS, is widely considered unsuitable for life-safety applications, for a variety of reasons. And unaided humans are perfect. Got it. The problem with the rail network is figuring out this backup system. Well, considering there's no backup system in place on many routes now, I'd say even the flakiest iPhone speed-alarm app is better than nothing. I can program my car to tell me if I exceed the speed limit. I'm sure multiple people will chime in to tell me several very good reasons why trains can't do that (or downmod me for asking.) In this case it might not have been enough to save the train, though, if the speculation is correct about the engineer being temporarily knocked out due to hitting his head while ducking a rock that might or might not have been chucked through the windshield. Wow, it's 2016 and I just typed that. I feel like I fell down a rabbit hole that leads straight to the 1890s.
Animats 11y ago
Usually, by communicating with RFID devices that sit between the rails. Most of these require no external power or connections; they just report their location. Some have connections to the signal system and report the status of signals and switches ahead. The ruggedness required of railroad lineside components is very high. They have to resist rain, snow, ice, flooding, hurricanes, vandalism, snowplows, and the machine that replaces the track ballast.[1] There's no reason the Northeast Corridor shouldn't have had PTC years ago, though. That's a busy line, and since it's electrified it has lots of wayside equipment already. There's resistance from the American Association of Railroads about equipping long freight lines out west and in the south, some of which don't have much traffic. That doesn't apply to the Northeast Corridor. Speed limit enforcement isn't new to railroading. Many subway systems, including NYC's, have had it for many decades. It's crude, based on timers between signals, but it works. Subways tend to have so many short signal blocks that block-based speed control works reasonably well. Above-ground lines have much longer blocks. Freight rail in open country can go miles between signals. [1] https://www.youtube.com/watch?v=UbfCX3WRL7g https://www.youtube.com/watch?v=UbfCX3WRL7g

NamTaf 11y ago

Driving a train, with multiple connected bodies together, is a fair whack different to driving a car. You have to forecast your decisions a lot more lest you introduce some nasty dynamics that can absolutely cause derailment (i.e.: excessive run-in) if extremely bad. Secondly, the approach that rail takes all over the world is to have highly interlocked fail-safe systems. Refer to safety integrity levels. [1] Track permission systems operate at SIL 4. It's EXTREMELY hard to 'write an app' that starts ticking the SIL boxes. The GEs of the world sink an incredible amount of money into automating train control and train driving. Still, it comes slowly because of the sheer complexity of hammering out every single corner case. [1]: https://en.wikipedia.org/wiki/Safety_integrity_level https://en.wikipedia.org/wiki/Safety_integrity_level