PTIS (GPS Tracking) On The Commuter Rail Discussion

Discussion relating to commuter rail, light rail, and subway operations of the MBTA.

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Re: Commuter Rail live mapping / tracking on Google Maps

Postby diburning » Wed Jan 02, 2013 8:53 pm

My phone is only a year old and had not hit the market very long (two months) when I got it.

My phone is not rooted although I have installed every update sent to it by my provider (T-Mobile)

I am reading that I can upgrade to 4.0.x (Ice Cream Sandwich) through Samsung so I'll try that. T-Mobile lists it as an optional upgrade so it never prompted me to do it. I'll just try that.
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Re: Commuter Rail live mapping / tracking on Google Maps

Postby StefanW » Wed Jan 09, 2013 1:00 pm

StefanW wrote:I'm spending all my time on an entirely new version of my app that will animate the markers in real-time, instead of re-drawing the entire page each time. (Stay tuned for that!)


If anyone wants to play around with my live-animation version, feel free:
http://www.people.fas.harvard.edu/~wuensch/T/live-train-map-beta.html

It's really basic right now, with none of the cool features in my first version... but it doesn't re-draw the entire page to show you an update, and that is a huge help.

As before, comments welcome. Over time I'm going to be bolting on all the same features onto this new version, but it will take a while.
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Re: Commuter Rail live mapping / tracking on Google Maps

Postby StefanW » Tue Feb 26, 2013 9:57 pm

I gave myself a slap-upside-the-head earlier tonight... I realized that I could make the red marker-clusters turn on & off with a keypress!
20 minutes later, done! I think this is a really useful new feature. I wish I had thought of this months ago.

Now if the red clusters of markers are showing (which happens when there's lots of train markers close together) you can press Shift (either left or right Shift) and the clusters will pop to the individual markers - and then back again when you release the Shift key.
http://www.people.fas.harvard.edu/~wuensch/T/live-train-map.cgi

I would love to know what people think - and especially if it doesn't work!

Also if there's other kinds of shortcuts or features you'd like to suggest, please do. Feel free to post or PM. Thanks, and I hope it's useful!
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Re: Commuter Rail live mapping / tracking on Google Maps

Postby FP10 » Wed Feb 27, 2013 6:16 pm

I don't ride the commuter rail all that much, but I live a stones throw from Beacon Park. I'm having so much fun watching the trains approach, then feel my house shake each time. It's also interesting to see just how many trains get held up at Market St where the line drops to a single track.
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Re: GPS Technology on the Commuter Rail

Postby StefanW » Sat Mar 02, 2013 4:58 pm

(This seems to be the proper thread for this post.)

While watching the new Rotem coach 1800 just now I saw this weird condition happen.
http://www.railroad.net/forums/viewtopic.php?f=65&t=51136&p=1154518#p1154518
StefanW wrote:1800 appears to have PTIS logged in for train 1409, but that's not the revenue 1409 trip. CTC 1642 appears to be the revenue trip.

The computers that aggregate the PTIS data really get confused at times like this when there's more than two consists on the same line sending the same train numbers! The consist with coach 1642 appears to be on time based on its position, with the 1800-1724 consist running about 10 min. behind it.

That's made the prediction system all mixed up, because my app is saying:
Train 1409 outbound to Fitchburg departed from Concord at 4:23 PM, 10 min. late. Scheduled stop was at 4:13 PM. Control Coach 1642 reporting


So it seems like the data from 1642 is getting clobbered by the additional report from 1800/1724.


Also, it seems like the PTIS on coach 1724 was logged out just before Concord. The 1800/1724 consist was moving together from at least Waltham to Concord. Probably the MBTA computers can't handle when the PTIS goes out in the middle of a trip so they keep sending that coach's position as if it were valid.

Here's a couple of screen shots from my app, one showing the coach numbers and one showing the trip numbers. I don't think I've ever seen a situation where three different coaches were all reporting the same trip, and all so nicely spaced along the line. :-)
Attachments
1409-coach-numbers.jpg
Duplicate PTIS data for train 1409 2013-03-02 showing coach numbers
1409-coach-numbers.jpg (116.05 KiB) Viewed 1681 times
1409-train-numbers.jpg
Duplicate PTIS data for train 1409 2013-03-02 showing train numbers
1409-train-numbers.jpg (122.06 KiB) Viewed 1681 times
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Re: PTIS (GPS Tracking) On The Commuter Rail Discussion

Postby StefanW » Fri Apr 05, 2013 12:33 pm

I just read some bad news regarding the Commuter Rail data feed... They have updated it so that duplicate trip data will be eliminated. This is a Bad Thing because it means that very likely we'll lose the ability to track coaches regardless of revenue / non-revenue status! For example the Rotem CTC 1800 was only able to be tracked because it was reporting a bogus or duplicate trip number. Also I've seen consists deadheading in the past that I don't think would be visible now.

This was on the MassDOT Developer Google Group as part of the feed update announcement:
Developer at MBTA wrote:"Duplicate" trains (the same trip being listed twice with two different vehicles) eliminated.


I posted a plea to keep any / all data in the feed, and just flag duplicates so the developer can decide how to handle that data in their app. Hopefully they will find a way to do it, otherwise things like my mapping app will be much less interesting to us rail fans.
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Re: PTIS (GPS Tracking) On The Commuter Rail Discussion

Postby sery2831 » Sat Apr 06, 2013 1:42 am

Alright... So if there is duplicate data none of it will be let through?

Today I had three different sets, and all three the PTIS units did not work.
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Re: PTIS (GPS Tracking) On The Commuter Rail Discussion

Postby StefanW » Fri Apr 26, 2013 5:39 pm

sery2831 wrote:Alright... So if there is duplicate data none of it will be let through?

Today I had three different sets, and all three the PTIS units did not work.


Not sure yet... I'm still trying to figure out (by inspecting the data manually which is tough) how or if they are removing duplicate trip reports.
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Re: PTIS (GPS Tracking) On The Commuter Rail Discussion

Postby StefanW » Fri Apr 26, 2013 5:48 pm

Now there's another thing they have changed in the data feed... the "lateness" figure!

Within the last 24 hours the lateness numbers changed to be apparently all rounded to the nearest 5 minutes. It used to be very granular numbers (1, 2, 9, 17 minutes late for example) and now it's just 5, 10, 15, 20, etc. (and 0 for on time).

Personally I think this sucks. I'm going to complain to them.
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Re: PTIS (GPS Tracking) On The Commuter Rail Discussion

Postby StefanW » Tue May 14, 2013 10:23 pm

Here's something new that folks might find useful...

Because I got annoyed at the MBTA live train data feed which failed again earlier today (Tues. May 14) and dropped all GPS and prediction data, I quickly wrote new code to show all train info for trips that don't have any GPS position and can't be mapped. This way if you are looking at a blank Google map at least you'll know what trains are NOT showing up.

Now on my app http://www.people.fas.harvard.edu/~wuensch/T/live-train-map-beta.html you'll see a section just below the map which says "There are trains for which the MBTA is not getting and/or sending position data" and a button to show (or hide) the list of all train trips which don't have position data available. The thing I think is new & unique is that I'm sorting the list of upcoming trains by time of next arrival/departure - with all North side and South side trains combined. This way you can see the scheduled action on the entire system even if there's no data that can put it on the map.

If anyone has suggestions on how to display the train info better, please let me know!
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Re: PTIS (GPS Tracking) On The Commuter Rail Discussion

Postby Backshophoss » Tue May 14, 2013 11:48 pm

Do you intend to track the "Cape Flyer" when it starts up to their stations past Middleboro(End of MBCR track)??
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Re: PTIS (GPS Tracking) On The Commuter Rail Discussion

Postby StefanW » Wed May 15, 2013 5:08 am

Backshophoss wrote:Do you intend to track the "Cape Flyer" when it starts up to their stations past Middleboro(End of MBCR track)??


I certainly hope I can! It's all up to the MBCR. If they have coded the PTIS systems with data for the Cape Flyer trips, and if that data shows up in the feed, my app should pick it up automatically without me needing to do anything. At worst perhaps I have to add a new data source on the back-end of my app. I'll be watching the data for any trips like that every weekend! All I can say for now is: stay tuned for more.
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Re: PTIS (GPS Tracking) On The Commuter Rail Discussion

Postby StefanW » Wed May 15, 2013 5:19 am

Backshophoss wrote:Do you intend to track the "Cape Flyer" when it starts up to their stations past Middleboro(End of MBCR track)??


One more thing... It's unfortunate that the MBTA doesn't send PTIS position data out unless the coach is on a revenue trip. They assumed when they designed the system that people would only ever care about *trips* when we rail fans care more about *equipment*. (At least that's what my app wants to track.) I've spoken to them about this, showed them my app, and asked for raw GPS & speed data regardless of revenue status. They were generally supportive of the idea. I don't know if / when it will ever happen, but at some point maybe (and that's a huge "maybe") we'll be able to see each and every coach, any time the PTIS gear is even just turned on. If that was the case, tracking the Cape Flyer would be easy.

Another thing I've considered is "crowd sourcing" position data from the iPhones being tested by the train crews. I doubt it would ever happen (mostly because of personal privacy issues) but I could imagine an opt-in tracking system where the GPS position of a Conductor's iPhone contributes to the train location data. It would be far less accurate than the GPS receiver on top of the coaches however.
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Re: PTIS (GPS Tracking) On The Commuter Rail Discussion

Postby JBConn » Wed May 15, 2013 1:12 pm

I infer from this thread that cab cars carry GPS antennas and PTIS equipment. Do locomotives?
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Re: PTIS (GPS Tracking) On The Commuter Rail Discussion

Postby StefanW » Wed May 15, 2013 1:39 pm

JBConn wrote:I infer from this thread that cab cars carry GPS antennas and PTIS equipment. Do locomotives?


Nope, only cab (control) coaches have PTIS gear. I believe the primary reason is that it uses the data connection provided by the on-board cellular data gear that also supplies the WiFi. (I don't believe the PTIS unit is connected via WiFi - that would be too unreliable. I believe the PTIS is hard-wired into the cellular modem gear.)
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