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Metro's platform sign problem

For several weeks, Metro riders have been telling me they think there's something wrong with the platform signs that display train arrival times. I've been getting complaints about the electronic signs for years. The most common complaint is that the sign says the next train will be eight cars long and it turns out to be six.

But the new complaints are different. First of all, there have been a lot of them. Second, they focus on errors in the arrival times. They say the signs show a train boarding when it left several minutes earlier, or that the signs show a train three minutes away when it is at the platform.

Metro spokeswoman Lisa Farbstein says the transit authority knows there's a problem but hasn't been able to figure out the cause yet. Metro refers to the situation as a latency problem. Data about the train movements are delayed getting from one point to another within the passenger information display system.

"It appears the issue is with messages backing up in the PIDs server," Farbstein said in an e-mail. "These latency issues typically occur during rush hour when there are lots of trains and lots of rider messages being displayed. Our IT department is analyzing the situation to determine the solution."

Farbstein said that so far the tech people have been able to figure out that the system is generating accurate predictions of train arrival times. So the problem appears to occur after the computer system makes the prediction and before it gets displayed on the platform signs.

Here are a couple of messages I got from riders during my online chat Monday:

Q. Metro Message Boards: For over a week now the Metro message boards have been out of sync on the Red Line. The sign may indicate a train is arriving or boarding when there is no train in sight. The arrival times have been off about two minutes (if it says 3 minutes it really is 1 minute).

Q. PIDS: They've been screwed up on the Orange Line too. I arrived at my station the other day only to find out that the train that was supposedly arriving was already gone.

Here are a couple of comments that have appeared here on the blog:

"My orange line train was supposedly 4 minutes away last night as it arrived in the station."

"The train arrival boards at Farragut West and Federal Center SW are also out of sync with the actual trains."

David Alpert also has written about the PIDs problem on his Greater Greater Washington blog. And UnsuckDCMetro wrote about The Crazy PIDs These Days.

By Robert Thomson  | September 29, 2010; 3:50 PM ET
Categories:  Metro  | Tags:  Dr. Gridlock, Metrorail  
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I noticed it on the red line this morning. Curiously, the mobile next train prediction on my phone was accurate, but the display on the platform was not. It was still showing a train that was no where to be seen as arriving...then a minute or two later as boarding...then a minute or two later the display on the platform seemed to catch up to the online display and was accurate by the time the next train came (there was a 6 minute wait for that train during rush hour).

Posted by: informedtraveller | September 29, 2010 3:56 PM | Report abuse

From Dr. Gridlock: informedtraveller's description matches up with what Metro is saying. The IT people found that the other versions of the train information system -- like the mobile next train prediction -- were performing accurately. So they think the information going into the system is accurate. The problem is getting current information to the platform displays. (No prediction on how long it will take to fix.)

Posted by: Dr_Gridlock | September 29, 2010 4:06 PM | Report abuse

I noticed the first day that it happened. I made it to Arlington Cemetery (blue line) when I was supposed to be on an orange line train. That first day there were about 60 other people that did the exact same thing. I only noticed I was on the wrong train because there was a lot of screaming(from other riders)when we arrived into Arlington Cemetery and it made me look up.

Posted by: ashdaleuf | September 29, 2010 4:12 PM | Report abuse

same experience as informedtraveller. the metro application on my phone are absolutely correct and precise. the pids have been off by 1, sometimes 2 minutes. i've noticed it the most at gallery place, but also columbia heights where i depart from in the morning.

i've seen some people get on a yellow line train when they thought it was green because of the pid!

Posted by: xrvax | September 29, 2010 4:24 PM | Report abuse

"These latency issues typically occur during rush hour when there are lots of trains and lots of rider messages being displayed."

I’m calling B.S. on this comment. My lousy old cell phone can download a dozen short messages (140 characters) in 10 seconds but WMATA’s server can’t handle the awesome onslaught of messages (sarcasm!) that must be displayed on the PIDs during rush hour? The PIDs were outdated the day they entered service but they aren't THAT bad.

I guess I’ll just hope someone brings their kid to work to fix the PID server.

Posted by: augrim08052010 | September 29, 2010 4:26 PM | Report abuse

I also noticed two weeks ago, on the Blue/Orange line downtown, that number of cars listed for the train was wrong. It said there was a two-car orange line train arriving. It was actually 6 cars...haven't seen a two car train since the ill-fated two-car late night train experiment a few years ago.

I also have been using the mobile service for both buses and metro, and it has inaccurate data for both. The buses lately have been completely off.

Posted by: kahuna613 | September 29, 2010 4:29 PM | Report abuse

From Dr. Gridlock: kahuna613, I think that problem of getting the train length correct has been with us since the PIDs were introduced. That's a problem of the approaching trains communicating properly with the PIDs computer system. (Yeah, I know, if it's been a problem for so long, how come it's not fixed?)

Most of the complaints I've gotten about the PIDs over the years have been similar to what you describe. I think most riders by now know they're not going to see a two-car train, but it's really annoying to position yourself for an eight-car train and then have a six arrive, so you have to hustle down the platform.

Posted by: Dr_Gridlock | September 29, 2010 5:02 PM | Report abuse

Other than getting some good IT people (not cheap), I can't offer any constructive criticism of WMATA's PID problem. Sorry.

NextBus is a joke with buses vaporizing (and materializing) on a regular basis. I'm convinced one of my J3 drivers never turns on his NextBus GPS because he is hiding from his girlfriend while the J2 gets held at Bethesda so it slips off the system.

Posted by: augrim08052010 | September 29, 2010 5:38 PM | Report abuse

The part about the PIDs being all wrong that *really* drives me up the wall is not knowing where to wait for a train. Since all trains pull to the front of the platform, if you go to wait for car 7 or 8 of an 8-car train you're not getting on a normal 6-car train if it comes. And car 6 is always stuffed beyond capacity in the mornings, so I tend to wait up at car 1 unless it's an 8-car train. Which I can't know it is if the signs are wrong...

Posted by: EtoilePB | September 29, 2010 10:18 PM | Report abuse

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