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| Update on WMATA almost accident from a while back (1403632) | |
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Update on WMATA almost accident from a while back |
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Posted by TransitChuckG on Thu Jul 28 15:57:35 2016 Crash |
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Re: Update on WMATA almost accident from a while back |
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Posted by zuckie13 on Thu Jul 28 17:05:38 2016, in response to Update on WMATA almost accident from a while back, posted by TransitChuckG on Thu Jul 28 15:57:35 2016. Ok, I'm confused maybe. I get we havn't had Metro running with ATC, but why isn't the system using the on board cab signals to at least enforce these stop signals?This would be like NYC tying down all of the the trip arms. |
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Re: Update on WMATA almost accident from a while back |
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Posted by Jackson Park B Train on Thu Jul 28 17:28:21 2016, in response to Re: Update on WMATA almost accident from a while back, posted by zuckie13 on Thu Jul 28 17:05:38 2016. WMATA thinks it is "regional rail" not a suibway, so no tripper arms. And apparently no electronic substitute.As to the union issue, actually I believe that part of the "contract" between the worker and the union mandates that they defend him. Not very different from a "public defender". That said, IF the incident was as described, he should never work there again, nor should anyone found to have falsified maintenance records. WMATA will likely need to have a mass turnover of personnel as part of reorienting the "corporate culture" of the system top to bottom. |
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Re: Update on WMATA almost accident from a while back |
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Posted by WillD on Thu Jul 28 21:45:07 2016, in response to Re: Update on WMATA almost accident from a while back, posted by zuckie13 on Thu Jul 28 17:05:38 2016. WMATA is running with Automatic Train Control. ATC is composed of Automatic Train Operation, Automatic Train Protection, and Automatic Train Supervision subsystems. The ATO system is the subsystem currently not being used, but all other aspects of the ATC system are fully in operation.ATP does enforce wayside signals for most cases. It uses the cab signal system to maintain train separation and enforce speed limits. But I believe WMATA's cab signal system does not force the vehicle to remain standing with a command speed of zero. Instead, after bringing the train to a stop the system allows the T/O to continue at a restricted speed. It is up to the T/O to continue on sight not exceeding some speed and avoid contact with rail defects, other trains, and stopping short of wayside signals at stop. |
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Re: Update on WMATA almost accident from a while back |
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Posted by Sand Box John on Fri Jul 29 01:15:00 2016, in response to Re: Update on WMATA almost accident from a while back, posted by zuckie13 on Thu Jul 28 17:05:38 2016. Ok, I'm confused maybe. I get we havn't had Metro running with ATC, but why isn't the system using the on board cab signals to at least enforce these stop signals?Cab signal will stop a train in manual mode. The thing is an operator can still proceed after being stopped by the lack of a speed command at a speed no greater the 15 MPH. There is no such thing as a zero speed command, the lack of the presents of speed command is interpreted as a zero speed command by onboard hardware. There also in no stop and stay command. The reason why this functionality exists is because virtually all of the non revenue track on the railroad in not configured to transmit speed commands to the trains. Operating at no greater then 15 MPH with ATP enabled allows trains to operate on track not configured to transmit speed commands. John in the sand box of Maryland's eastern shore. |
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Re: Update on WMATA almost accident from a while back |
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Posted by zuckie13 on Fri Jul 29 09:49:35 2016, in response to Re: Update on WMATA almost accident from a while back, posted by Sand Box John on Fri Jul 29 01:15:00 2016. Thanks, that explains why this was able to happen.Seems like a bad design not to have the capability to really enforce a stop. Does this even go for interlockings? They probably should have the capability to transmit a zero speed command that means "really, don't move", while still allowing the 15MPH when there is no command. |
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Re: Update on WMATA almost accident from a while back |
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Posted by Sand Box John on Fri Jul 29 10:22:40 2016, in response to Re: Update on WMATA almost accident from a while back, posted by zuckie13 on Fri Jul 29 09:49:35 2016. Does this even go for interlockings?Like I said there is no stop and stay command. You can go anywhere on the railroad at a speed no greater the 15 MPH with ATP enabled when no speed commands are present. This would not be an issue if trains were being operated in automatic mode. John in the sand box of Maryland's eastern shore. |
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Re: Update on WMATA almost accident from a while back |
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Posted by Bzuck on Fri Jul 29 10:27:06 2016, in response to Re: Update on WMATA almost accident from a while back, posted by zuckie13 on Fri Jul 29 09:49:35 2016. I don't believe there are trip arms on NYCTA once you are in a yard, just as you enter. |
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Re: Update on WMATA almost accident from a while back |
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Posted by The Silence on Fri Jul 29 11:22:48 2016, in response to Re: Update on WMATA almost accident from a while back, posted by Bzuck on Fri Jul 29 10:27:06 2016. in the strictest sense there are ones in every yard, usually of the fixed verity. |
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Re: Update on WMATA almost accident from a while back |
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Posted by merrick1 on Fri Jul 29 13:07:53 2016, in response to Re: Update on WMATA almost accident from a while back, posted by zuckie13 on Fri Jul 29 09:49:35 2016. It's really no different than being able to key by a trip arm. And once you've keyed by you can go as fast as you want. |
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Re: Update on WMATA almost accident from a while back |
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Posted by Michael549 on Fri Jul 29 20:54:14 2016, in response to Re: Update on WMATA almost accident from a while back, posted by Sand Box John on Fri Jul 29 10:22:40 2016. Here's the part I'm confused about.In the NYC subway, when there are track switches, there are double-headed signal fixtures that indicate the usual route and diverging route. When the switch is set for the diverging path - as I understand it that switch can not move if there's a train on that pathway headed in the direction where a crash is likely to happen. Unless you are saying that a train operator could "key-by" a red-signal and then take the track switch and then head straight for an opposing train. I don't believe you're saying that, but I want to be clear. -- In the WMATA accident, there's the non-ability it seems to stop a train that has dis-regarded a red signal AND taken a switched pathway that placed the train in the path of an on-coming train. In the past I know that "keying by" was used in the past to close the distance between two trains, say train 1 is at the platform, and train 2 is literally right behind it. In this example, both train 1 & train 2 are traveling in the same direction. I don't believe (or won't to believe) that "keying by" was used in operations where there were are opposing trains with riders on board. Mike |
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Re: Update on WMATA almost accident from a while back |
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Posted by Sand Box John on Sat Jul 30 00:17:24 2016, in response to Re: Update on WMATA almost accident from a while back, posted by Michael549 on Fri Jul 29 20:54:14 2016. Unless you are saying that a train operator could "key-by" a red-signal and then take the track switch and then head straight for an opposing train. I don't believe you're saying that, but I want to be clear.That's exactly what I am saying. Provided to points of the turnout are set to direct the train in that direction. John in the sand box of Maryland's eastern shore. |
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