Green Line LRT

[mlseim]

I'm starting to plot the Blue Line. It appears to be placing Google Markers on the rails (unlike part of the Green Line).

Here are the Blue Line markers:
http://www.catpin.com/blueline2.php

The 2 real-time locations are:
http://www.catpin.com/greenline.php
http://www.catpin.com/blueline.php

Now, the issue is how accurate are the reporting times. The API documentation (of which is very little) does discuss a possible 5 minute delay of reporting, yet another document says the reports are more often. The API has a rule that you cannot query it faster than 30 seconds, or it may block you.

Two queries about 1 minute apart put the same Southbound Blue Line train several miles apart between markers. No way the Blue Line could have traveled that fast in 1 minute ... so now I am not so sure about the reporting times.

[mulad]

Did the timestamps update, though? Were they just 1 minute apart too, or did they have a wider delta?

It was very interesting to see your map of Green Line positions. You may as well fire off a note to Metro Transit and point it out, and in the interim just add the extra (roughly) .0075 degrees latitude east of I-35W. It sort of makes sense that the system would treat the Green Line differently than the Blue Line corridor, and that's right where it branches off, but it's still really strange that it's offset like that. Similar to what I mentioned before, they might have inadvertently used the wrong coordinate system for the new track, but used the correct one for the Blue Line.

[Silophant]

The downtown section of the Blue and Green lines will be closed again this weekend, though it will be opened back up Saturday afternoon/evening for the concert at Target Field. It's been just five weeks since the last time this happened.

[twinkess]

The downtown section of the Blue and Green lines will be closed again this weekend, though it will be opened back up Saturday afternoon/evening for the concert at Target Field. It's been just five weeks since the last time this happened.

This is annoying. Why can't this maintenance be done at night?

[twincitizen]

At least partially, because unlike most rail systems, we choose to run ours all night long. Many/most American rail systems stop all service by roughly 1am, including WMATA, BART, etc. Minneapolis-St. Paul is among a very small group of rail systems in the US that runs 24-hour service (NYC subway, Philly, Chicago Red & Blue lines, maybe a couple others but not many)

Though that raises the question: Why can't we just have overnight shutdowns as needed? Why do they need to shutdown daytime service?

[mlseim]

I'm trying to learn how the system works. At any given time, like let's say at 10am today, how many trains are actually moving on the green line? One train in each direction, or are there 4 trains spaced apart? Is there a chart or graphic that shows it, or an explanation for a novice like me?

[Didier]

Though that raises the question: Why can't we just have overnight shutdowns as needed? Why do they need to shutdown daytime service?

Speculating out loud: Overnight workers tend to be paid a slight premium, and while that premium might amount to less than a weekend of lost revenues, perhaps Metro Transit has also determined that it can't attract enough quality workers for overnight shifts?

I've wondered this too, why we don't just go all out on certain construction projects and go around the clock to get them done asap. Some combination of the above two factors seems a somewhat reasonable explanation.

[FISHMANPET]

I'm trying to learn how the system works. At any given time, like let's say at 10am today, how many trains are actually moving on the green line? One train in each direction, or are there 4 trains spaced apart? Is there a chart or graphic that shows it, or an explanation for a novice like me?

The headway is 10 minutes, which means a train comes every 10 minutes. So to figure out how many vehicles you need, you take the total round trip time and divide by the headway. The round trip is 90 minutes (45 minutes each way) so at a minimum you need 9 trains. They're probably running with 10 or 11 though in reality, as if it was a 100 or 110 minute round trip, so that there's a break time at the end of the line for the drivers, as well as a time for late trains to catch up (if a train is late it just waits less at the end, so it can leave on time again).

[mlseim]

Thank you, that helps me understand it.

[LRV Op Dude]

I'm trying to learn how the system works. At any given time, like let's say at 10am today, how many trains are actually moving on the green line? One train in each direction, or are there 4 trains spaced apart? Is there a chart or graphic that shows it, or an explanation for a novice like me?

The headway is 10 minutes, which means a train comes every 10 minutes. So to figure out how many vehicles you need, you take the total round trip time and divide by the headway. The round trip is 90 minutes (45 minutes each way) so at a minimum you need 9 trains. They're probably running with 10 or 11 though in reality, as if it was a 100 or 110 minute round trip, so that there's a break time at the end of the line for the drivers, as well as a time for late trains to catch up (if a train is late it just waits less at the end, so it can leave on time again).

When 10 minute headways there are 12 consist on the line. Consist is LRV set. Operators gets 14 minute recovery at each end.

[LRV Op Dude]

Though that raises the question: Why can't we just have overnight shutdowns as needed? Why do they need to shutdown daytime service?

Speculating out loud: Overnight workers tend to be paid a slight premium, and while that premium might amount to less than a weekend of lost revenues, perhaps Metro Transit has also determined that it can't attract enough quality workers for overnight shifts?

I've wondered this too, why we don't just go all out on certain construction projects and go around the clock to get them done asap. Some combination of the above two factors seems a somewhat reasonable explanation.

Most luckily reason for the shutdown is because of the skyway construction for stadium near 4th and Chicago.

[FISHMANPET]

Which makes a... 118 minutes
round trip, I guess I kept something from my transit planning class.

Sent from my phone

[mulad]

That makes sense for the operators, but do the train consists match? At Union Depot, the operator of the arriving train gets off and is replaced by someone else.

[mlseim]

I contacted metrotransit about the error in GPS latitude for a portion of the Green Line. They told me that someone is already working on it. Meanwhile, I figured-out the error is latitude+0.007795

Here is my NexTrip API/PHP/Google Map mashup showing all trains in service ... in real time :
http://www.catpin.com/greenline.php

Every once in a while, the NexTrip API throws a bad GPS location, so I remove them if they pop-up.

I guess my next step now is to sit on University Avenue and see how close the API times match what I see with my eyes.

In any event, I'm learning a lot about making a mashup.

[Silophant]

Most luckily reason for the shutdown is because of the skyway construction for stadium near 4th and Chicago.

Ah, that makes sense. I was wondering what kind of track maintenance they could be doing that would require multiple nights to do it, but could also be stopped, leaving the tracks functional, in the middle.



Very cool, mlseim!

[MNdible]

Here is my NexTrip API/PHP/Google Map mashup showing all trains in service ... in real time :
http://www.catpin.com/greenline.php

Very cool. Thanks for sharing your progress!

[JT$]

I contacted metrotransit about the error in GPS latitude for a portion of the Green Line. They told me that someone is already working on it. Meanwhile, I figured-out the error is latitude+0.007795

Here is my NexTrip API/PHP/Google Map mashup showing all trains in service ... in real time :
http://www.catpin.com/greenline.php

Every once in a while, the NexTrip API throws a bad GPS location, so I remove them if they pop-up.

I guess my next step now is to sit on University Avenue and see how close the API times match what I see with my eyes.

In any event, I'm learning a lot about making a mashup.

That map is awesome.

[mlseim]

Update on the NexTrip API concerning the Green Line.

The programmers at NexTrip have repaired the offset in Green Line GPS latitude. All GPS locations are now correct.

Map corrected now ... using the current GPS locations from the API:
http://www.catpin.com/greenline

The actual NexTrip API (where I'm getting my Google Map locations):
http://svc.metrotransit.org/NexTrip/Veh ... ormat=json

Update times for the train locations appears to be about 1-2 minutes. They advertise updates under 5 minutes, so they are doing a pretty good job of updating their API. Every once in a while, a train drops-off the list. Possibly, a train doesn't report? Or query is caught during an update? The next minute it's OK again.

Note: Blue Line: http://www.catpin.com/blueline

[mamundsen]

This is awesome!

[mlseim]

I actually don't really have a use for the maps. I just wanted to experiment with the NexTrip API and see what I could "mashup" with Google Maps.

If anyone wants a copy of the PHP/Google Map V3 script, email me through my website:
http://www.catpin.com/contact.php

The script is one file plus a few graphic images for the markers. It's PHP, so it has to run on a real website (shared webhost or your own web server).