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| Re: FastTrack nonsense. (1458440) | |||
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Re: FastTrack nonsense. |
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Posted by Stephen Bauman on Fri Dec 15 20:14:49 2017, in response to Re: FastTrack nonsense., posted by AlM on Fri Dec 15 19:18:40 2017. A couple of thoughts.1. the train position measurement unit is: stopped at a particular station; in transit to the next station and incoming to the next station (when the IRT signs turn orange). 2. measurements are taken every 30 seconds. So, any data would be at least 30 seconds old. However, most systems download the data once per minute. This makes the data between 60 and 90 seconds old. 3. the display unit precision is in minutes. 4. updated schedules are bundled with train position data. Schedules are quantified to the nearest half minute (with the exception of the L-Train). 5. The IRT feed schedules do not distinguish between arrival and departure times. The L-Train schedules 15 seconds dwell time for each stop. 6. There are 8 separate feeds that have to be polled for the entire system. (Probably 9, when the #7 Train becomes operational.) The format for each of the feeds are not consistent. 7. If there are diversions, the trip id can change making tracking virtually impossible. Sometimes the trip id is mangled without any diversions. 8. The MTA was supposed to archive previous feeds on a daily basis. That stopped about two years ago. A private individual started archiving the feed and made the data available. However, that stopped in June of this year. That's why my AWOL report is MIA. I tried to collect the data directly from the MTA's master feed. However, I don't have the bandwidth or a machine I can dedicate to simply collecting the data. I've started developing a cloud based app to duplicate the previous archived feed. It's a new experience for me, so there's a learning curve. I hope to finish the archive retrieval soon, if I can muster the determination. |
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