Fully underground subway systems are more resilient
The Metrorail heavy rail transit system is a mix of underground and above-ground sections. In the worst winter weather conditions, in the past they have hunkered down and only run the part of the system that is fully underground, within DC (although some sections in the suburbs are also underground, primarily the Orange Line in Arlington County, Virginia).
The last couple storms, including the one this past weekend, they have shut down the entire system for a time, not even running the underground section, because of fears that potential power outages could strand trains and riders.
I am not criticizing WMATA for shutting down, even though it turned out we didn't have widespread power outages (likely because the snow was soft and powdery).
You can try to keep the system running for as long as possible but on the backside, it means more downtime as the system works through the recovery period.
With an anticipatory shutdown, there is more uptime overall.
Still, with the benefit of hindsight, it's unfortunate that more parts of the system weren't built underground.
For example, if the section of the Red Line from Union Station to Silver Spring (between Silver Spring and Wheaton actually) had been built underground, then the entire east leg of the Red Line could operate during the worst of winter storms.
Similarly, the new Silver Line segment in Fairfax County was built above-ground and in aerial sections for great lengths. In the snowstorm--at least 20 inches in most places, and more than 2 feet in others--It turned out to be the most vulnerable section of the system and will be the last to be fully operational as the system reopens.
Too bad that winter-time resilience wasn't one of the factors considered in the debate over whether or not to build the Silver Line underground ("Rail Tunnel Debate Raises Larger Issue," Washington Post, 2006). It would have cost much more, true, but would have been able to operate in adverse conditions.
STM in Montreal is the best example in North America of building a heavy rail system completely underground, which they did in part because the city experiences some of the worst winter weather conditions on the continent. As a result, the Montreal heavy rail system is much more resilient than heavy rail systems like DC's.
-- Using public transit in winter | Société de transport de Montréal
Ironically, because the system was built entirely underground and train cars are not exposed to weather--rain, snow, or sun--the cars were not built to be weatherproof. (That means no air conditioning either.)
Two lessons for transit system design engineering derived from hindsight concerning the Metrorail system. (1) Fully underground systems are more resilient in adverse winter weather conditions. (2) Two track systems--one in each direction--lack redundancy, at least one additional track would allow for express service and more efficient operations when tracks or trains are not functioning.
Labels: emergency management planning, public safety, the robust and resilient city, transit design and engineering, transit operations, weather
posted by Richard Layman @ 5:17 PM&Permanent Link
18 Comments:
I agree with your comments about fully underground systems, but generally in North America it's not a choice - budgets are so meager, and construction costs so high, that many worthy transit projects are not funded at all.
I don't agree with the comments about express tracks. This seems to be a common refrain in the DC blogosphere, probably because so many Washingtonians are familiar with the NY subway. But no other major metro system on earth has express tracks as New York does. Redundancy is achieved by building additional subway lines, often paralleling existing ones. This has the additional bonus of bringing rapid transit to new areas.
E.G. I've always liked the way the Red and Green lines intersect at Fort Totten... Red Line riders on the Wheaton branch have an alternate route to downtown during a disruption.
First, I admit this is an academic argument. And in port cities like NYC or Boston, a fully underground system might not be susceptible to snow, but would be susceptible to water.
Given the population density, it's not possible in the DC area to have the kind of redundancy offered in NYC by having multiple lines in close proximity.
Except in the core (and at certain crossing points like Fort Totten), you're going to have one line with a transit shed of many miles in each direction.
The point of redundancy is to foster system uptime. As I have written before, the way the system is configured, without redundancy, it must always be maintained at extremely high levels of good repair, and the transit cars must always be in tip top shape too.
That's virtually impossible, because enough money isn't allocated to maintenance and capital equipment. Cars are expected to be in use for at least 40 years, etc.
Therefore, if you want more uptime as the system degrades, you need at least one more track.
Granted, I am not a civil engineer, but from the standpoint of operations, I'd argue that the system as it is configured, will not be able to reach regular ridership of say 1.2 million people/day as was originally forecasted and the system was allegedly built to provide.
That's why for redundancy purposes multiple tracks would have been good.
By comparison the Montreal system is smaller but carries more riders. That's because it is somewhat monocentric (see the argument in Belmont's _Cities in Full_) while the WMATA system is polycentric, a hybrid combination of suburban commuter rail and urban heavy rail.
Cities like NYC, Montreal, Chicago, Philadelphia, and Boston instead serve more distant points with commuter rail.
But the fully underground nature of the Montreal system and the decision to not air condition the cars (because that would have required bigger tunnels) ends up making it much more reliable (because engineering-wise it is simpler), even without a third track.
In the event of snow, yes, an all-underground system would be more resilient. But that doesn't mean it was a mistake to build above-ground.
How many snow shutdowns has Metro had in nearly 40 years of operations? Not too many. The additional cost to bury tracks (particularly when perfectly good above-ground ROW is available, like the Red Line) likely cannot be justified solely to avoid a few snow days.
The same is true of 4-track lines. I hate that this always comes up. NYC didn't build 4-track trunk lines for reslience, they built them for capacity. And they did so because those subway lines replaced proven, well-traveled elevated train lines (as well as Streetcars) in Manhattan.
Montreal is an interesting case, but it's a mistake to compare the calculus on snow to DC. Montreal gets an average of 85 inches of snow each winter. DC gets just 15. Montreal has an average of 60 days with snowfall per winter; DC just 8.
There's also no case for the Silver Line tunnel to actually make the system more resilient. It would still need to connect to above-ground sections.
@AlexB, what would be interesting is to see how much the District spends compared to a Montreal for winterization.
You can see that in the CABI dock design, where the paint finishing on docks can't handle the street salt. Bases are rusting out.
The BIDs seem to be more effective yesterday in doing some basic tasks than DC workers.
Again, I said this was an academic argument. Yes, you have to deal with the Cost-Benefit Analysis over many decades.
And yes, the Silver Line thing is moot because WFC and EFC are above ground. (Although in my discussion of an RER type line out from Union Station into Northern Virginia, you could do "cut and cover" under I-66.)
But there is no question we haven't built this kind of resilience into the system.
2. With the proviso that I am not a civil engineer, as far as multiple tracks go, in my discussion in other blog entries and in the comment thread above, the point I make is that the WMATA system is unlikely to be able to achieve the planned daily ridership numbers of 1 to 1.2 million in a two track system unless it is in a state of good repair higher than what is typical of transit systems in North America.
Montreal is an exception because it is 100% underground. It is a two track system. But because it is fully underground it can run in all weather conditions, and because they chose to also not air condition the cars along with not needing to engineer the cars to withstand weather, the cars are simpler and less prone to breakdown.
Yes, NYC subways have the number of tracks it does because of density. But you can't argue that the additional tracks don't contribute to redundancy, leading to more uptime overall.
Yes, the system "doesn't" need as much redundancy within a single line because many parts of the system have other lines in parallel within a close distance, at least in Manhattan, but that occurs only in those cities with great density, like London or Paris.
And interconnections between lines in those systems further aids redundancy. By contrast, because the distance between lines is so significant and each line has very distinct transit sheds with minimal overlap (except in the core), interconnections between lines in the Metrorail system wouldn't contribute much to redundancy.
Yes, NYC's subway is more redundant.
But so what? The circumstances that lead NYC to build those kinds of subways were unique. No other city is going to build that way for very good reasons. There's no real lesson there for what WMATA should've done or should do going forward.
Yes, we haven't built snow-resilience into the system.
But so what? These big snow events are rare.
Metro could absolutely get to 1 million daily trips on the existing system, with all efforts focused on maintenance. How? Denser land uses around existing stations.
Actually as use intensifies around Metro stations, at least in the core, people will ride subways less per capita, as they are able to accomplish more in tighter "mobility sheds" while not using heavy rail.
I rarely ride transit, although it's a bit much to overgeneralize. Between biking, walking, and car sharing (for trips of two or more people) I don't find much need to ride the subway or bus.
German cities have subways that have more than two tracks- but it seems that many ignore this
In terms of specific DC recommendations, yeah, double tracking is a horse that bolted a long time ago.
Thinking about snow can be helpful -- certainly as Richard suggests parts of the Red line (as well as blue near the pentagon) could be better snow proofed to allow full time service.
A new tunnel crossing could also be evaluated in terms of snow operations.
Probably suffering from Snowcrank, but I'd strongly push back against and say we do need some critical thinking here:
1) Again value of a city and peacemaking Snowball fights in dupont circle are a waste -- or are they? That is what makes city life attractive. What makes paying metro a premium to run service is the ability to do it in bad conditions.
2) Lack of a plan on pedestrian access in the L'infant city (the outer city controlled snow removal).
3) Ability of a government to function (Flint) --- again what we are seeing in DC proper is blowing through chunks of cash but with little results. Again contra Malouf piece it is always going to be more expensive in a city to do snow removal but there is a real lack of knowledge, expertise and leveraging here. The reeves center was cleared in 2 hours -- DC had a very impressive collection of mini plows. They didn't do anything else.
the residential alley areas almost NEVER get snow removal services- in Gessford Court during 2010 we had an emergency room doctor who lived there and about 15 of the residents of the alley and surrounding houses all worked to clear a path for her to get her car free to get to her critical work. The city leaves itself open to litigation because the city workers still regard residential alley citizens and areas as third class low priority undeserving of services or of respect- sure hope that no one suffers from this neglect on the part of the Ward 9 government
It's a blizzard of course -- in 1888 -- that convinced NYC to go underground. The recent blizzard here did cause NYC to cut back all above ground transit (including buses) after a certain point as well as ban all non-emergency car traffic. There does seem to be recognition up here, that cutting off the transit system wholesale, really hurts workers that still have to get to work. Maybe we just have more non-white collar workers who still need to be on the job?
It's still surprising to me -- 23 years later -- how poorly DC handles bad snow storms. Sure, DC isn't Minneapolis, but it still gets annual heavy snow fall. Much more frequently than we do in NYC, and still the only response is: shut it all down.
charlie -- wrt "critical thinking" it's why I wrote the "maintenance of way" piece almost 6 years ago. It was a quantum jump in approach from previous annual pieces on the subject.
(It helped that I was working in Balt. County at the time, dealing with the same issues there, and extremely inconvenienced taking transit between DC and Towson--bike, except during snows, train, bus, subway, sometimes light rail.)
When I was thinking about running for City Council, one of the stunts I wanted to do was use a small tractor equipped with a snow brush to demonstrate during snow events that we could do a lot better.
WMATA and DC have lots of small equipment. We just don't have plans for extending their use beyond the primary placement. (E.g. they have tractors for the Takoma Metro site, but don't use them on land not controlled by WMATA--leaving key intersection crosswalks blocked.)
And this snowstorm, the snow clearance for the Coolidge school and park complex was exemplary. Pretty much superb. I take some credit for it, because my evaluation of what they do goes into my annual writing on the subject. They have improved every year since I started writing--from doing virtually nothing, to complete sidewalk clearance over the equivalent of 8 city blocks.
I suppose next year I need to do another major codification because bits and pieces since 2010 go into the annual piece.
And yes, that kind of piece should have run in GGW in advance of the season, not in "after action" reports, which yes, aren't big picture enough and don't have enough analytical heft.
===
Christopher -- the running of the Montreal subway during a major blizzard in 1971 convinced people they made the right choice to build underground transit!
charlie, if the outer city controlled snow removal, it was only on the arterials and collectors. The side streets were only minimally treated.
And yes, catchment areas around Metro stations received no special treatment for pedestrians, unless the land is controlled by WMATA.
Link to "maintenance of way?"
you're right on the "outer city". That was snow-crank.
Snow removal is an object lesson on how stupid and medicore our city leaders and workers can be.
The positive news is Ft. Myer Construction probably made about 3M this week.
http://urbanplacesandspaces.blogspot.com/2010/02/maintenance-of-way-agenda-for-walking.html
I know I wrote about this in 2009, and I imagine probably 2008. (E.g., DDOT used a photo I used the post from 2008 or 2009 subsequently--it was from the Boston Globe.)
I testified in 2011 and each year when I write about it, I add stuff. E.g., in the post in December, which you commented on, I included discussion of heated sidewalks.
(Note on that post I just added in the comments something on "electric concrete" which is something that would make a lot of sense for multiunit residential buildings. I put it in the comments so that I know I will mention it this coming December...)
e.g., 2013, http://urbanplacesandspaces.blogspot.com/2013/01/snow-reminds-us-of-necessity-of.html
testimony in 2011, http://urbanplacesandspaces.blogspot.com/2011/02/testimony-on-winter-sidewalk-safety.html
2014, http://urbanplacesandspaces.blogspot.com/2014/02/agenda-setting-snow-clearance-in.html
FWIW, you've commented on many of these pieces--to my benefit, as always.
electric concrete:
http://www.csmonitor.com/Technology/2016/0126/Throw-away-the-shovel-How-electric-concrete-melts-snow
note that I sent the article to the 11th Street Bridge Park people too...
I keep blowing off what I am supposed to be writing, but maybe I'll do an update of the MOW piece over the weekend.
with climate change, I don't know if the DC area will experience more snow or less.
Anyway, apparently as part of the same "polar vortex" Hong Kong experienced its lowest temperatures ever, and they weren't prepared.
http://www.scmp.com/comment/insight-opinion/article/1906446/hong-kongs-embarrassingly-poor-response-cold-snap-must-not
This is a great post about subway system.
Seoul subway serving the Seoul Metropolitan Area is the most extended subway framework on the planet.
Visit here-"buy medicine online".
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