Posts in category Transit
Equipment designed to detect track problems alerted Metro employees to the dangerous condition that led to a train derailing last month, but an employee deleted the information by mistake, according to a report from WMATA on the incident.
According to the report, the Track Geometry Vehicle spits out warnings as it rolls over the tracks if it detects any problems. The worst kind, like this one, are "Level Black."
However, the machine also reports "Level Black" sometimes when there's no problem at all. For example, when it goes over a switch, the track geometry there isn't the same as on straight track, and there will be innocuous warnings. Or a curve is supposed to have a little extra room. A human operator is supposed to interpret the raw data and decide where there need to be repairs.
In this case, the operator made a mistake, and deleted this "Level Black" from his report while keeping in several others which got fixed. The system still stored all of the raw data, but there was no process where anyone else would compare the operator's list of repairs against the original raw data. Therefore, his mistake meant that nobody else saw the problem, either.
The operator in question and his supervisor both resigned, according to WAMU's Martin di Caro, and other employees may face discipline.
This problem is different from, but sounds somewhat similar to, one of the problems before the 2009 Red Line crash. There, the signal system would regularly report errors, but so many that workers started ignoring them. After all, nothing had been wrong the last few thousand times that error popped up. Until, that is, something was very wrong.
There, they were ignoring real errors thinking they were normal. Here, the official protocol was to ignore some errors of this type. But it seems like a dangerous situation in any case when staff get used to ignoring errors.
Both humans and computers will look at the track data more closely
To deal with this, Metro is adding processes where a supervisor will review the report with the operator after the run and compare it to the raw data. That way, it's less likely (though still possible) for a real problem to get ignored.
Just doing that sounds risky, since if the Track Geometry Vehicle regularly spits out "Level Black" errors that both the operator and supervisor are supposed to ignore, it's very easy for them to just get used to ignoring them and gloss over a real one once in a while by mistake.
That's why it's nice to see in the report that Metro is also working to write computer code that can know about the usual spots where not-really-errors crop up. If a specific switch or joint always gives the same error, and that error is actually not a problem at all, then rather than reporting one every time which the operator is trained to delete, maybe the system should report it differently, so that the real Level Black errors stick out more.
Metro will also remind staff that the automated machines are supposed to only supplement, not replace, the visual inspections that also happen. It's easy to stop paying such close attention if you've got a machine that can do it, but the machine can fail.
This report is welcome
We've been complaining for some time that WMATA top officials just say "we've got this" and don't share much information publicly. This report is much more forthcoming about the details of what's going on, and while that's no substitute for having avoided the problem in the first place, at least being open about the findings now is a positive step.
To continue to build trust, riders deserve to also hear more in the future about how well some of these efforts are going. Many of these findings relate to building the "safety culture" that former General Manager Rich Sarles was supposedly instituting.
The public needs some more assurances about how a safety culture is being built, as it happens. We all can hope Metro actually does build up that safety culture and make these processes succeed; given WMATA's low level of public confidence, continuing to provide more information can help people actually believe it.
After years of delay and construction problems, the Silver Spring Transit Center will finally open next month, bringing together local and intercity buses, MARC commuter rail, and the Red and future Purple lines. To get travelers ready, Metro put together this diagram showing how it will work.
Silver Spring is one of the region's biggest transit hubs, bringing together dozens of bus and train lines and serving 60,000 passengers each day. It'll become an even bigger destination when the Purple Line opens in 2021. First envisioned nearly twenty years ago (and several years behind schedule), the transit center (named for former senator Paul Sarbanes) provides a single place where all of those services meet.
The transit center will have three stories, each with its own entrance from the street. On the ground floor, with an entrance on Colesville Road, you'll be able to find Metrobus routes serving Maryland, some of Montgomery County's Ride On routes, MetroAccess, and a shuttle to the Food and Drug Administration's campus in White Oak. This is where the Red Line entrance will be, as well as some bike racks.
On the second floor, with an entrance on Ramsey Avenue, you'll find Metrobus routes serving the District, additional Ride On routes, and the University of Maryland shuttle, as well as intercity buses like Greyhound and Peter Pan. This floor connects to the MARC train platform and has an escalator down to the Metro entrance.
The third floor, entered from Bonifant Street, will have taxis and a kiss-and-ride. The transit center also has a TRIPS commuter store where you can get transit schedules and buy tickets. All three floors connect to a portion of the Metropolitan Branch Trail, which will eventually connect Silver Spring to Union Station.
Strangely enough, you won't be able to get MTA commuter buses at the transit center. They'll continue to stop a half-block away at Colesville Road and East-West Highway.
On Tuesday, we posted our sixty-fifth photo challenge to see how well you knew Metro. I took photos of five Metro stations. Here are the answers. How well did you do?
This week, we got 21 guesses. Six people got all five. Great work, Peter K, Justin..., Roger Bowles, AlexC, JamesDCane, and Mr. Johnson!
Image 1: Archives
This week had a theme: knockout panels. Each of the featured stations has provisions for future entrances. For each station, the image we featured is where slightly different walls make that visible.
The first image shows the knockout panel for a future southern entrance to Archives station (it would be in the vicinity of Constitution Avenue and 7th Street NW). This knockout panel is fairly distinctive because of the full outline of the mezzanine opening in the endwall of the station. The mushroom-shaped panel is easily visible from the platform. Note, the white rectangle extending outward from the wall has nothing to do with the panel. It's part of an antenna for providing cellular coverage in the station.
Thirteen got this one right.
Image 2: Federal Triangle
The second image shows the provision for a future entrance to Federal Triangle station. Unlike at Archives, this future entrance would make use of the current mezzanine, and would not require a new fare control area. This entrance was planned at a time when the federal government intended to tear down the Old Post Office to complete the long-planned Federal Triangle complex. Since the building is landmarked, this entrance is unlikley to ever be constructed.
We featured this knockout panel in week 6. Only a few stations have knockout panels. You could've narrowed this down to Federal Triangle because of the elevator here. The only similar knockout panel is at Navy Yard (pictured below), and that knockout panel is not located next to an elevator.
Nine knew this one.
Image 3: Pentagon City
The third image shows the place where a future southern mezzanine could be installed at Pentagon City. Like at Archives, this would be a completely new entrance, with its own fare control. The main clue here is the orientation of the station. There are very few side platform stations in Metro, and even fewer have the waffle-style vault. So that should have helped you narrow down the options pretty significantly.
We featured these knockout panels in week 12. Eleven guessed Pentagon City.
Image 4: Navy Yard
The fourth image shows one of the knockout panels (yes, there's more than one) at Navy Yard station. This entrance would lead to an escalator at the corner on the north side of M Street at Half Street SE. Originally, fare control at the western entrance of Navy Yard was at the mezzanine level (where the picture was taken), however, when this entrance was reconstructed to accommodate crowds coming from Nationals Park, fare control was moved to street level. If this entrance were built, the faregates would need to be at street level as well.
Clues for figuring this one out included the jagged area on the bottom of the panel (for structural supports) and the fact that you could see a second mezzanine at the opposite end of the station. Very few underground stations have entrances at opposite ends of the trainroom. So that should have helped a lot.
Nine figured it out.
Image 5: Bethesda
The final image shows the well-disguised knockout panels at the southern end of Bethesda station. These panels will soon be used to build a southern mezzanine with a connection to the Purple Line station just below the surface.
Other than having noticed these before, or having figured out the theme, the only thing you could do to narrow this down was to note the architectural type. This was clearly an Arch I station, a type which appears only on the Red Line's Shady Grove branch. You can tell this is Arch I (4 coffer vault) because the first crossbar is very high on the wall. At an Arch II station, like Georgia Avenue, the first crossbar would be lower, and a second would be visible above.
Fifteen guessed Bethesda.
Next Tuesday we'll have five more photos for you to identify. Thanks for playing!
Note: You can find the leaderboard, submission guidelines, and other information at http://ggwash.org/whichwmata.
If you've noticed Metro's performance declining over the past several months, you're not alone. In order to open the Silver Line last year, Metro has had to run more train cars longer, and the extra mileage put onto them has meant their breakdowns may affect your service more often.
To get an idea of the overall picture, the graph above shows the WMATA on-time performance for all rail lines since 2011. Silver Line service started in July 2014 and from that point forward you can see a clear 3% decline in on-time performance systemwide (that doesn't include the big dip on the far right, which is the result of the harsh temperatures of last winter).
The dip in performance relative to before and after the Silver Line opened primarily affected the Blue, Orange, and Green lines. System-wide, on-time performance dropped from 92% to 89%:
Putting more spare trains into service sets the stage
Transit agencies try to keep a spare ratio of around 20-25%. Some cars are going to need to be in the shop for unscheduled repairs, preventative maintenance, or inspections. No transit agency operates 100% of its cars in service at any given time.
When WMATA opened the Silver Line it had not yet deployed the new 7000 series cars needed, so the agency dipped into its spare pool temporarily until enough new cars were set for service.
With a lower spare ratio, Metro doesn't have enough time to do preventative maintenance or inspections on cars. And when some need maintenance that can't wait, there may not be enough cars to build a train or the train may break down on the mainline, causing delays.
One impact of the lack of cars is that an increased number of scheduled trains do not operate (DNO). The data shown in the graph below are the number of trains that were canceled or otherwise did not operate on the six lines between August 2012 and July 2015.
A train might be marked as DNO for a variety of reasons, but one main cause can be attributed to not having enough cars available to make a full train. For instance if there are too few cars available to make up a train, that train is not able to run. Alternatively, WMATA might only have 1000 series cars available and no others to act as the head and rear of the train; thus, the train would not be able to run.
Before July 2014, the Orange Line averaged 18 DNO trains per month. When the Silver Line opened in July 2014, that number spiked fairly dramatically. Since then the Orange Line has averaged 45 DNO trains per month, and Vienna station itself hit a maximum of 50 DNO trains in the month of June 2015. The overall system average has increased from 40 DNO trains per month to 141.
When a train doesn't operate, it creates a gap in service averaging just over six minutes. So instead of waiting, say, six minutes for a train, customers have to wait up to 12 minutes. During that period the platform gets more crowded, and when the next train shows up, it has to carry a larger load.
The more crowded a train is, the longer it dwells in stations, which exacerbates the delay, and can cause bunching. Crowded trains can be more likely to be offloaded themselves as passengers hold the doors trying to get on and off. With the overall system averaging system averaging 7-8 DNO trains per day in June and July 2015, the delays can really start adding up.
So what's causing the number of DNO trains to spike?
There aren't enough train cars
There are several reasons why performance on the rail system is suffering, but the main item we can draw from this data is that the railcar spare ratio is too low.
WMATA does not currently have enough train cars to run the full system including the Silver Line. The first phase of the Silver Line requires 64 train cars to operate, which were to have been delivered before its opening. Today, only 32 of these cars are in revenue service.
WMATA says that the current system requires 954 train cars to operate at peak service and the agency has approximately 1,140 available for revenue service use. Metro plans for 24% of the total cars to be out of service for maintenance, spare, or unscheduled reasons, leaving 868 available. But with 954 cars required, that means the operating spare ratio is only 16% and sometimes even lower when more are pressed into service.
With fewer cars available to put into service when others break, we are more likely to see a domino effect of breakdowns. Fewer trains may be available to run at peak hours due to equipment constraints (and thus marked DNO, like when the 4000-series cars were taken out of service earlier this summer). In addition, each car is likely to have less available time for preventative maintenance meaning the chance of breakdown increases over time. To take a look at another part of the equation, the reliability of the railcars that Metro runs varies, the topic of discussion in a recent post.
While the data suggest WMATA doesn't yet have all the cars they need, help is slowly arriving. The fourth 7000 series train entered service on the Green line this past week, and more are coming, especially once the test/commissioning track near the Greenbelt station is finished. Once at least 64 of the new 7000 series cars are in service, we should start to see a tapering of car-related issues and on-time performance should start to increase again. For all those having to deal with train delays, we hold our baited breath for relief to come.
A modified version of this post ran earlier on Stephen's website. He tweets online about Metro at @MetroReasons.
It's time for the sixty-fifth installment of our weekly "whichWMATA" series! Below are photos of 5 stations in the Washington Metro system. Can you identify each from its picture?
This is a themed week.
We'll hide the comments so the early birds don't spoil the fun for the rest of you.
The answers will appear on Thursday. Good luck!
Information about contest rules, submission guidelines, and a leaderboard is available at http://ggwash.org/whichwmata.
Monday morning, the fourth of the #newtrains, also known as the 7000 series, entered service on the Green Line, joining the others on the Blue, Red, and Orange lines. If you're wondering where to find one (or all four) of the trains, look no further.
These tables show the scheduled runs of the 7000 series trains. For a variety of reasons, Metro could change this schedule at any time without notice, and if there are delays on any of the lines, they can affect when the train will show up.
The first table shows the morning period on the Blue and Orange lines. Note, for trips toward Franconia and Vienna, read down. For trips toward Largo and New Carrollton, read from the bottom up.
|5:57||6:49||8:21||8:55||Federal Center SW||7:31||8:05||9:55||10:13|
|6:33||8:57||Van Dorn St||6:55||9:19|
|7:14||9:20||East Falls Church||7:40||9:48|
|7:17||9:23||West Falls Church||7:37||9:45|
The next table shows the evening commute period on the Blue and Orange lines.
|3:33||3:37||5:43||5:57||Federal Center SW||4:53||5:07||6:59||7:31|
|4:09||6:33||Van Dorn St||4:31||6:55|
|4:02||6:08||East Falls Church||4:28||6:34|
|4:05||6:11||West Falls Church||4:25||6:31|
Here's the schedule for the Red Line #newtrain. It hasn't changed since we shared it with you in June.
|7:47||x||3:27||5:47||Rhode Island Ave||8:34||x||4:10||6:34|
Finally, here's the schedule for the Green Line's #newtrain.
|5:36||7:21||x||2:49||4:39||Prince George's Plaza||7:07||8:55||x||4:25||6:13|
|5:53||7:38||x||3:06||4:56||Mount Vernon Sq||6:50||8:38||x||4:08||5:56|
In a month or so, Metro should add a fifth train. If they provide the schedule data publicly, we'll keep you up to date with a revised set of schedules.
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- Here are the answers to whichWMATA week 65
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