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Metro ponders new tunnels and connections

Before long, the Metro system will be bursting at the seams, besides those spots where trains are already stuffed to the gills. What can we do?

Photo by ep_jhu on Flickr.

To figure out some solutions, Metro's planning department has been analyzing many different alternatives for fixing the capacity bottlenecks. They've been posting the presentations to their Technical Advisory Group on PlanItMetro, allowing us to get a look at some of the possibilities even before they're fully analyzed.

To start with, Metro definitely needs to upgrade power systems to accommodate more 8-car trains, and build enough railcars to make up those trains. Other key capacity fixes that have been talked about for years include pedestrian walkways between Farragut North and West, and between Metro Center and Gallery Place.

Even with all of this and the "Yellow and Orange Line Service Increase" plan, trains will have 22% more demand than capacity by 2040, particularly on the Orange Line between Court House and Rosslyn, Yellow between Pentagon and L'Enfant Plaza, and Green between Congress Heights and L'Enfant, especially the segments around Waterfront and Navy Yard.

In the past, we've discussed some of the possibilities. One long-discussed option is to separate the Blue Line into a new tunnel of its own through Georgetown, the Mount Vernon Triangle, and H Street.

Left: Possible separate Blue Line. Right: Possible separate Yellow Line.
Click on an image to enlarge.

Another would be to build a separate tunnel for the Yellow Line next to the current Yellow and Green tunnel between L'Enfant and Mt. Vernon Square. This would allow more Yellow and Green trains since ethey would no longer have to share tracks.

However, it would cost a lot of money yet not provide access to any new areas or deal with the growing transit demand as Southwest and Near Southeast become dense residential and job centers. Nor would it do anything about the heavy demand at Union Station, which will only increase as MARC and VRE add capacity.

Another option would be to route the new tunnel through SW and SE, along I Street SW/SE, then turning north past the Capitol to Union Station. Some trains over the bridge could take this route, while others could take the current route. Already, Metro plans to make some of the trains from Franconia-Springfield go over the bridge, so the Franconia trains could be the ones to take the 7th Street route while the Huntington trains went to Union Station, for example:

Click to enlarge.

One drawback of this option is that this new tunnel will not carry the maximum frequency of trains. That's because there's a limit to the number of trains through the King Street-Pentagon route, some of which would go to Rosslyn, some to L'Enfant, and the rest in the new tunnel.

The study estimates 6-minute headways during peak and 12-minute off-peak. By comparison, the Red Line has 2.5-minute headways peak and 6-minute off-peak.

In general, this is a drawback of the way the system was originally designed where different lines (except Red) share tracks. Many links don't get the maximum possible number of trains. To fix that, Metro could separate more lines with new tunnels. Or, they could add more switches so that different routes could use the available capacity:

Click to enlarge.

This option adds four track connections. Three, between Waterfront and the 14th Street bridge, between the bridge and Arlington Cemetery, and between the cemetery and Court House, would enable a new service between Branch Avenue and Dulles Airport.

A fourth lets trains on the Dulles line turn toward Vienna to maximize trains on both of the northern Fairfax branches. New stations connected to West Falls Church and Pentagon for the new lines would also accommodate transfers.

This option gives Virginia a lot more service and the whole system more flexibility to route around problems. On the other hand, it's likely to lead to more people transferring at more stations, and creates more crowding at Rosslyn since many trains will now bypass it. (Or can Rosslyn get another station like Pentagon does in this option?)

The clear question with all of these is whether Metrorail expansion is even right to consider, or whether money is better spent on light rail and bus service. Dan from BeyondDC always argues that for the cost of one heavy rail line, you can get streetcars and light rail all over the place.

Metro planners also took a look at many of these options, some of which are in the presentation already online while others will come up in future phases of this plan. Stay tuned for more great nuggets of information as the study progresses.

David Alpert is the founder of Greater Greater Washington and its board president. He worked as a Product Manager for Google for six years and has lived in the Boston, San Francisco, and New York metro areas in addition to Washington, DC. He now lives with his wife and two children in Dupont Circle. 


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Adding more services via interline connections to maximize track capacity may sound good, but it would require some very precise scheduling to make happen.

I prefer the philosophy of separating all of the interlined sections, so that long-term, each line is on it's own tracks and shares them with no one - e.g., each line will operate as the Red Line does today.

I'd also note that the interline connections in those presentations did not model particularly well.

One other comment about the new Yellow line options. It's true that the new line through downtown doesn't open up new territory for Metro, but it also takes people directly where they want to go. I was optimistic about the option that routed the Yellow line towards Union Station, but it did not model well at all and actually exacerbated crowding at the Rosslyn segment (since more riders transferred for the more direct connection to downtown).

The real question for serving new territory with those lines is what options exist for extending that new Yellow line northward - where will it go? That's where the lucrative new Metro territory is.

by Alex B. on Jan 24, 2011 11:44 am • linkreport

Adding some express service would permit trains and people to get where they need to be (e.g on reverse commutes), and get people where they need to be, faster. This would be especially important in rush hour or when there is some delay as there is a huge amount of additional delay when a crowded train pulls into a crowded platform. If you could pass through various stops, or service a crowded platform with an empty train, you could alleviate sudden bottlenecks.

How to do this? Well, you would need extra track and tunnels, but not everywhere: just enough to provide passing space, plus perhaps some additional linking of existing lines.

by SJE on Jan 24, 2011 11:46 am • linkreport

the heavy demand at Union Station, which will only increase as MARC and VRE add capacity would be better handled by MARC run-through to L'Enfant Plaza, Crystal City and Alexandria. That's a lot cheaper than a new Metrorail line and can be implemented a lot faster.

by jim on Jan 24, 2011 11:48 am • linkreport

Dan's got a good point. Would be a lot cheaper to build the DC streetcar network and extend it and/or LRT across the river into Arlington, connecting to the streetcar lines Arlington has planned.

That said, Metro's core capacity cannot be ignored. Ideally, we'd have the missing connections in question, a new Blue Line, AND a new Yellow Line. If I had to prioritize between then, the top priority would have to be the missing connection at the Pentagon, followed by Rosslyn, then a new Blue Line. I don't see a new L'Enfant connection between the Yellow and Green Lines as being as heavily used or as important as these other three items. Lastly, I don't see much use for the missing connection at West Falls Church...not without an Orange Line extension west at least towards Fairfax City. But for that cost, you'd probably be better off running LRT to get western Fairfax County workers to Tysons.

Lastly, call me biased, but I'd like to keep my Yellow Line trains to Archives/Gallery Place/Mt Vernon Square...:o)

by Froggie on Jan 24, 2011 11:48 am • linkreport

re: the Yellow line toward Union Station, I don't think we should build any new stations around the Capitol until they agree to develop some of their surface parking lots.

by Gavin on Jan 24, 2011 11:48 am • linkreport

Kind of surprised that longitudinal seating in the cars isn't mentioned as an option. It would add a lot of capacity, be very low cost, and could be rolled out quickly. This is the kind of policy that a GM with real vision would roll out ASAP.

by Phil on Jan 24, 2011 11:50 am • linkreport

I know people through around express-local configurations like it's the easiest thing to do, and I know that it isn't the easiest thing to do. But how hard is it, actually? Is it easier than building new tunnels where there weren't any before?

I'm not sure how cities like New York did it, but I'm pretty sure our two-track lines are as wide as the street. So building more tunnels would hit building foundations. Maybe the new tunnels could be under the old ones? That'd be a project.

by Tim on Jan 24, 2011 11:51 am • linkreport

Thanks for the post, David. I'm glad you're reading our site and publicizing our efforts. Could you please provide some links from this page back to the blog posts on our site where you downloaded the PPTs? It would be nice if your readers could easily find the original documents you write about.



by Michael PlanItMetro on Jan 24, 2011 11:57 am • linkreport

Thanks, Michael. Sorry for the link omissions. I've added some links.

by David Alpert on Jan 24, 2011 11:59 am • linkreport

I agree with the other Phil and have been saying this for a long time. However, it seems that WMATA is resistant to the idea.

M Street must happen, and the addition of Georgetown would solve, or at least ameliorate, one of the District's worst traffic problems. If the Green and Yellow Lines are to separate, it would seem to make more sense to have them overlap in the following manner:

Cross at a new station near Ohio & 14th Street Bridge
Green up 14th, connecting to existing line south of Columbia Heights and following it north to Greenbelt.
Yellow follows existing line, then running north up Georgia to Silver Spring and then up MD29 to White Oak.

The only problem with this is that it would eliminate the current U Street station and leave the line underneath U Street, but this could be used for redundancy. However, a new stop could be built at U & 14, perhaps a better location.

by Phil on Jan 24, 2011 12:06 pm • linkreport

The problem with Dan's point, which is true to a degree, is that transit service expansion in the metropolitan is really two different questions (which I discuss in my writings on transportation planning at the regional, metropolitan, suburban, and center city scales), a question of scales of service and therefore planning:

- developing jurisdiction specific transit plans (e.g., Fairfax doing streetcar and lightrail instead of worrying about extending the Metro past Vienna) that are appropriate to their needs; while still

- planning at the metropolitan level the foundational transit services while maintaining the capacity of this system to be successfully, especially at the core of the region ("the Central Business District" in DC).

With regard to the former, Arlington probably is doing this the best so far, and in theory, DC, with its streetcar and Circulator planning initiatives, is also. (I am on record about flaws in the DC planning process.)

For the most part, plans to extend Metrorail service to outlying areas aren't part of a well balanced transportation planning process for either the outlying jurisdictions, or the footprint of the area currently served. E.g., the Silver Line extension could also have been used to develop and deliver a separated blue line in DC, but this was never on the table.

As far as rail improvements within the core of the region, and within DC specifically, it is to DC's advantage to do this as much as possible, as much as it makes sense, to get towards the Paris ideal of greater concentration of high quality fixed rail transit service. Streetcars, even light rail, aren't the solution for every need.

by Richard Layman on Jan 24, 2011 12:09 pm • linkreport

- "Virtual tunnels," hopefully to be upgraded to real tunnels
- MARC through-running to L'Enfant Plaza and Crystal City, and ideally integrating MARC and VRE into a single system
- Is the K Street transitway dead?

In the long term:
- New Blue, with your alignment
- New Yellow, with a tunnel under 9th Street, routed: L'Enfant, Archives, Gallery Place, then to the New Blue's "New Jersey Ave" station, Bloomingdale, Hospital Center, connect to Green at Petworth station, then up Georgia to Silver Spring and on to White Oak.

by EJ on Jan 24, 2011 12:19 pm • linkreport

In terms of new tunnels, what is the low hanging fruit? Or how do you define low-hanging fruit?

Is replacing car traffic / car trips the most important metric? new development? Handing overcapacity?

Isn't the Pentagon a dying destination? Real limits to growth there.

In terms of ongoing expenses -- which is what is killing WMATA -- finding ways to knife MetroAccess and replace bus drivers -- would seem to be most effective way to cut costs. That screams streetcars, no?

by charlie on Jan 24, 2011 12:26 pm • linkreport

Adding routes by building new switches enabling different origins/destinations would only increase headways for all trains, increased complexity and increased likelihood of disruptions! Bad idea overall!

There is a reason why the Red line is the service with the shortest headways (90 sec I believe), simplicity!

by Vincent Flament on Jan 24, 2011 12:27 pm • linkreport


Pentagon is still a huge destination, both for the amount of office space in the building itself, as well as the transfer point there for buses.

I'd also note that the Pentagon is in a rather key location - it represents a sort of choke point to enter the city. Given the large physical barriers (the river, Arlington Cemetery, National Airport), that's the one spot to cross the river. Development or not, it's a key location for the transportation system to be sure.

by Alex B. on Jan 24, 2011 12:37 pm • linkreport

Vincent: there might be a 90 sec headway on the Red Line, but I cannot count the number of times I have waited like a sardine at Metro Center while train after train stopped,completely stuffed with people. 20+ minute wait to actually get ON the train.

by SJE on Jan 24, 2011 12:38 pm • linkreport

I'd pull that light-green (lime?) line to Franconia-Springfield. People from Dulles are much more likely to be NoVa people than PG folks. PG folks fly from BWI.

I like the realignment of the Silver Line to the Convention Center. Why not all the way to Greenbelt. That way you'd get a decent transfer from Dulles to BWI. This re-alignment is even more fun when you add that alternative yellow (gold?) line to Union Station. Yellow could go from Huntington to Glenmont.

by Jasper on Jan 24, 2011 12:40 pm • linkreport

I think the only way to compare and contrast these plans is to attach dollar figures to each of them.

Truly, some of these plans are shockingly expensive! That doesn't mean we shouldn't do them, of course, but it does make comparisons a bit easier. Modeling usage is less certain, especially since the projections often exceed a 10-year horizon.

I know something Mr. Alpert has hit on is GRC (Governance, Risk Management and Compliance) and prioritization. The Board needs to look at Enterprise-wide problems, determine the most pressing challenges, and formulate a plan to fix them. COSO, The Institute of Internal Auditors has few resources that address governance and risk management problems. WMATA should take a page out of their book. Their website has some great free resources for those who wish to see "best practices" in the private sector. Check out this link for examples:

They need to do the same here. Where are the biggest congestion issues? What are the available solutions and how much do they cost? To what extent do they solve the problem?

In a very, very important sense, congestion and usage are key risks facing WMATA. In many ways, they're as important (or even perhaps MORE important) than safety! To copy COSO's terms, overcrowding is a potential risk and congestion is a key risk indicator. It's not so important that we pick COSO or ISO, or some other recognized risk management framework so long as it works.

At the end of the day, it all does come down to money. How much is there? How much for safety? Capital improvements excluding expansion? Expansion?

To throw in some of my opinion that's on a bit shakier ground, I think policy makers and taxpayers would be more willing to give WMATA more money if WMATA proved itself to be efficient. And I think WMATA might need more money to do that, which is sort of circular.

My suggestions would be start small. Address Federal safety concerns and develop a more robust governance/risk management structure. Then move slowly on other priorities. Connecting Farragut North and West should be a small, "achievable" improvement and a relative bargain.

ERM is difficult! I use private-sector standards because they're the most robust, but think of all the ERM/governance failures in the private sector in the last few years.

I would love to see how WMATA's Board and Management respond to the criticism they've both received in the last few years. Can they adopt a robust Enterprise Risk Management model that works? If the answer is yes, I see service expansion as extremely desirable, pretty much no matter the cost (within reason). If the answer is no, I see service expansion as a non-starter as it requires billions of taxpayer dollars.

by WRD on Jan 24, 2011 12:41 pm • linkreport

The Red Line currently runs every 180 seconds (3 minutes), but prior to the recent schedule adjustment (which netted more railcars overall), it was running about every 150 seconds (2.5 minutes).

by Matt Johnson on Jan 24, 2011 12:42 pm • linkreport

Pentagon may be waning as a destination, but there is a lot of logic behind making it a major transfer point, as suggested in that 100-year map yesterday -- very similar to the Atlantic Avenue station in Brooklyn.

Rebuilding current stations/tracks to a 3/4-track configuration is probably more work than it would take to build new lines a few blocks away, and therefore not a great idea.

The downtown Blue line needs to happen, and the alignment for it seems almost fortuitously obvious in the western parts of the city. The eastern portions of the routing are likely to be far more controversial. A new Yellow Line could take *several* routes, and would probably be a lot less politically viable for a host of reasons. It should eventually happen, but the downtown blue seems a lot more important (On the other hand, extending Yellow to Ft. Belvoir should be happening *now*).

I've always wondered why the single-service Red Line is considered holy and untouchable. These fantasy maps almost never show other services along the current red line's tracks. There's already a (potentially useful) Green-Red connection, and a (much less useful) Red to Orange connection. Given that it makes zero sense to ride the Red Line from end to end, I'm surprised that we haven't seen proposals to split it up to provide more sensible single-seat rides.

Also, good luck routing trains from Fairfax/Loudon to Anacostia. Political issues aside, would that even be a popular route?

by andrew on Jan 24, 2011 12:45 pm • linkreport

Looking at the Macrolevel picture, there will be fewer working Americans paying into the tax system over the next 10-20 years, and those who do pay will have sharply lower take home pay (boomers are retiring). In addition, salaries will be much lower in comparison to food, raw materials and energy (lifting of global economic standards).

With that in mind, we need to de-emphasize loss making transit services to small/remote/isolated populations regardless of perceived "need". For example, the night owl service is a fantastic social policy, but at it's heart it's an economic hole for Metro. The operation costs of supplying train service to maybe a few hundreds of people is economically unsustainable without heavy subsidies either from the riding public or public funding. Similarly, using bus service as a low cost subway option for low income people, instead of a "last mile" service to extend the reach of subway stations creates a redundancy which chokes metro.

Metro expansion is going to have to start overemphasizing the direct calculable economic benefit of certain expansions as the relate to *operating costs and capital costs*. Metro is already one of the least subsidized systems in the country, but at 55ish percent it's hardly self sustaining. Service needs to be added *only* where it is a net financial benefit to the system (ideally ridership pays for it's operating costs) based on real numbers of households that ARE going to ride it. That means a de-emphasis on social policy and an overemphasis on matching household commutes.

From an efficiency/ cost standpoint crowded trains and crowded stations are the best thing metro can have. Far flung stations served by trains with plenty of seats means there's overcapacity that's just wasting money. We absolutely need to add ring service at certain points around the beltway (Tysons to Lower Rockville, Shady Grove to I-95, probably other's in VA).

The growth that makes the most sense from a physical planning perspective often makes the least sense from a commuting perspective. We can't add stops that hang like an albatross over the next generation of commuters and the metro organization.

by Moving Ahead on Jan 24, 2011 12:50 pm • linkreport

@andrew that's essentially the route I would need (EFC-NYD), but I end up riding to Eastern Market instead.

Another EFC resident and commenter here rides down to Branch Ave, so that would be good for him.

Additionally, the routing allows for more capacity from anywhere along Dulles-Tysons to the Pentagon or to anywhere up to Court House in Arlington. If you don't have a route like that, you're limited in track capacity because all trains have to go to Stadium.

by Michael Perkins on Jan 24, 2011 12:53 pm • linkreport

Also, something to consider is how to deal with the times when Metro isn't packed to the gills.

For instance, although the Red Line has some of the system's shortest headways on weekdays, it's also generally got the longest headways on nights and weekends. Adding extra services and isolating lines could very well result in a less convenient system for off-peak riders.

Personally, I've been avoiding Metro on weekends lately, because I don't want to be stranded on an elevated platform in the cold for 20+ minutes.

by andrew on Jan 24, 2011 12:56 pm • linkreport

I find it interesting that Silver Line service in that final diagram would stop at Mount Vernon Square. I've often thought of a logical eastern terminus of that line to be in Greenbelt, with a simple bus connection to BWI from there. I see a benefit in being able to get from BWI to Dulles in as few transit seats as possible.

On that same vein, I think it would make sense to have a one seat connection between Union Station and all three airports. Integrating our transportation nodes could really keep this city moving.

by Dave Murphy on Jan 24, 2011 12:56 pm • linkreport

@Vincent: actually, constructing the switches to allow some routes to bypass the central core would result in better headways on many lines.

by Michael Perkins on Jan 24, 2011 12:57 pm • linkreport

The separated Blue line from Rosslyn to Stadium-Armory is still the best option.

by NikolasM on Jan 24, 2011 1:00 pm • linkreport


Long off-peak headways on the Red Line are an operational issue, not an infrastuctural one - well, they are so much as the delays are due to maintenance.

Point is, we should be planning to ensure that we can actually operate a higher level of service. In order to cut costs, I'd like to pursue full automation of all lines, but that's just me.

@Dave Murphy

What would the point of an IAD-BWI line be? You'd spend 2 hours on the Metro. There's absolutely no reason you'd take a local subway from one international airport to another.

At least the proposed DCA-IAD lines make some sense in that DCA is a domestic airport, but I still don't see any reason to make that connection. I don't see much reason to extend the Green line to BWI, period - just improve MARC service there. Get MARC to Metro-North type frequencies and we're talking.

by Alex B. on Jan 24, 2011 1:01 pm • linkreport

@alex; when I said "Dying" it was a bit too extreme. Not growing, and potentially shrinking. BRAC moves, more video-conferencing, etc. Turning it into a transfer point is interesting but I am sure DOD will muck it up. Is there a demand problem at Pentagon station now?

Moving ahead is quite right at looking at actual demand as a basis for new lines.

by charlie on Jan 24, 2011 1:02 pm • linkreport

@Michael Perkins:

@Vincent: actually, constructing the switches to allow some routes to bypass the central core would result in better headways on many lines.

I think you missed Vincent's point (and mine as well) - when the system is running at near peak capacity in terms of headways, all of those interline sections would have to be timed perfectly. The light green line from Dulles to the Navy Yard interlines with six different services in that diagram. You'd have nightmarish delays with trains waiting for the track ahead to clear.

A far better approach, in my opinion, is to give each service it's own tracks and provide service with substantial frequency, thus transfers between lines are not onerous or time consuming.

by Alex B. on Jan 24, 2011 1:05 pm • linkreport

@Alex B: I'm aware of the issue, I'm just saying that I'd rather have three or four minute headways on the EFC-Rosslyn segment and other segments with occasional delays at the zipper points than nothing. Doubling up enough tracks to give each service its own would cost on the order of dozens of billions of dollars, while reworking the three transfer points would probably be less than $5b and would increase system capacity by a lot on the outer segments.

by Michael Perkins on Jan 24, 2011 1:34 pm • linkreport


I don't see how the Pentagon itself is skrinking at all. BRAC moves won't be of consequence - someone else will occupy that space in Crystal City (which is a separate issue from the Pentagon transfer anyway).

Nevertheless, Pentagon remains a large choke point in the entire transportation system, whether for Metro or for cars (14th St Bridge) or for commuter rail. That's a key location, no matter what.

by Alex B. on Jan 24, 2011 1:36 pm • linkreport

Alex B. @1:01PM:

The single Rosslyn Y interline isn't just for Dulles to DCA. It provides a single seat ride from almost all NoVa stations to Dulles and from almost all NoVa stations to DCA, which MWAA ought to want (and therefore ought to want to fund?)


I was surprised that the single interline connection actually does better on the measures of effectiveness than the multiple interline connections. That plays into your comment of getting the timing right.

by jim on Jan 24, 2011 1:42 pm • linkreport


I don't think delays would be occasional, I think they'd be endemic. That Light Green line would have to zipper in and out six times over the course of the entire line. What's worse is that such a line touches all other lines (except Red), meaning that a delay on one of them then becomes a delay on all of them. I think it would decrease operational efficiency a great deal.

Yes, it would increase capacity on the outer segments of the system, but that's precisely where capacity is in excess. More capacity is needed in the core. A separated line, such as the new Blue line, would effectively double the Orange line's capacity while also adding more capacity to the core.

So, you could do something like the New Blue line at, say, $8b and solve two problems, or add all those interline connectors at $5b and solve only one - the one that's least pressing, as well.

by Alex B. on Jan 24, 2011 1:45 pm • linkreport


I think you are talking about headways here which unfortunately are a direct result of operational constraints.

As far as I know the minimum achievable headway that can be achieved is 85 seconds (L14 Paris). That assumes ATO and other features not currently present in the metro system. A automatic system such as London Dockland railway with more complexity barely achieves 2 minutes. (What is the status of ATO in DC btw?)

So my point still stands I believe. Complexity = less capacity.

by Vincent Flament on Jan 24, 2011 1:52 pm • linkreport

@Vincent Flament:
Metro can run trains about 90 seconds apart through much of the system. However, switches are set manually by the control center. That means that 135 seconds is generally needed between trains at those points.

by Matt Johnson on Jan 24, 2011 1:59 pm • linkreport


I'll have to defer to Sand Box John on this one, but I think Metro's ATO system is theoretically capable of 90 second headways. I know he mentioned seeing that in action once as a test, said it was quite impressive. Actually operationalizing that would be problematic given other constraints, hence the current max of ~135 seconds.

by Alex B. on Jan 24, 2011 1:59 pm • linkreport

@Alex B: Does zippering out involve delays or potential delays? I would figure trying to combine lines would be the limiting case. In that case, there's only three merges in each direction.

Right now the best you can hope for is 26 per hour from Rosslyn to Foggy Bottom, and no less than five are going to be coming from Arlington Cemetery. So that limits the capacity coming from Court House. Wouldn't being able to have some trains not go to Foggy Bottom mean that we could have more trains starting from Dulles or Vienna?

by Michael Perkins on Jan 24, 2011 2:29 pm • linkreport

Just a crazy question from a neophyte but what about trains longer than 8 cars? If the station platforms are too short couldn't an Amtrak like walk between cars be setup?

by Kevin Diffily on Jan 24, 2011 2:38 pm • linkreport

@ Matt

Under ATO or in normal operations? In Theory or in day to day practice? According to my expereience (granted only a little more than a year) I have never seen it happening...

by Vincent Flament on Jan 24, 2011 2:40 pm • linkreport


You bring up a good point. Think of it this way - you can add up the total level of service at each station, and it has to be less than 26 trains per hour.

So, look at that interline example. Starting at Dulles, you have 26 trains to allot amongst three services - Silver, Light Green, and Maroon. Let's say you go 10, 10, and 6.

The problem is then that you've got 20 total trains on the next segment (shared with Orange), which means you only have 6 trains going into downtown. That's not good at all. So, if you re-adjust those numbers from the first segment, you're not actually hitting that capacity.

As you move from each segment, the problem just gets worse and worse.

In the end, I'd suspect you'll find that the light green line would be at best scheduled quite infrequently (4,5, maybe 6 trains per hour at peak) - and that's no guarantee that each of those scheduled trains will hit their slot exactly and stay on schedule, avoiding cascading zipper delays.

I think this option will be a nightmare operationally, it will be confusing to riders, and although it's cheaper, it's still not going to be cheap. Instead, spend the money to separate the lines and do it right.

by Alex B. on Jan 24, 2011 2:49 pm • linkreport

It was disconcerting that in the projections for 2040 only 65,000 daily riders were expected to be riding streetcars/light rail lines, with over 700,000 riding Metro trains. An appropriate response to urban bottlenecks for essentially suburb-to-city transit service is to provide an alternate means for short-distance trips. There is no need to build a multi-billion dollar set of tunnels when high capacity surface transit would provide a better alternative.

by egk on Jan 24, 2011 2:52 pm • linkreport

To put it another way, drawing the colored lines on the map makes for a nice picture, but it ignores the very real geometrical constraints that such a system would face in operation.

Jarrett Walker does a great bit on the varying issues of emotion and cold, hard facts like geometry:

His case study is the BART extension to SFO, which uses an awkward wye alignment that cuts frequency in half for each of the legs and is very confusing for users, but it was a simple diagram that politicians liked - no matter how problematic it was in a technical sense.

Scotty said it best: "I cannah change the laws of physics..."

by Alex B. on Jan 24, 2011 2:54 pm • linkreport

@Vincent Flament:
Sorry. That would be ATO. They can run trains about 90 seconds apart under ATO. In some cases, that happens anyway when trains are backed up.

Headway is a function of block length, speed, and timing. So even if trains are leaving Grosvenor every 3 minutes, it's possible for there to be only 90 seconds between trains at Metro Center - if they're backed up.

by Matt Johnson on Jan 24, 2011 3:00 pm • linkreport

Here is an idea of mine for two new lines, one metro line that helps with the BRAC situation at Mark Center and one that would connect Union Station to Dulles Airport.

by NikolasM on Jan 24, 2011 3:31 pm • linkreport

@Alex B.:

Excellent link! It does put a lot of things regarding transit into proper perspective.

by Chuck Coleman on Jan 24, 2011 4:09 pm • linkreport

The Rosslyn and Pentagon turns should be built first, before any more tunnels under the Potomac or the District. If so, the Silver Line could run to Downtown via the Yellow and Green lines' existing tunnels. This would help alleviate the "Orange Crush" problem without the expense of relocating the Blue Line. But I do agree with Alex that these turns should only be added with expanded stations at both Rosslyn and Pentagon.

by Brian on Jan 24, 2011 4:25 pm • linkreport

What about moving half of the bus routes from Pentagon, Rosslyn, Silver Spring, Anacostia, Rhode Island Ave, Friendship Hgts, Wheaton, New Carrolton and Addison Road.

Each of these stations has between 10-20 buses that stop there while the nearby stations have between 0-5 why not spread out some of the routes so that you dont have masses all going to the same station.

by kk on Jan 24, 2011 5:17 pm • linkreport

Vincent: I think that my point still stands. While a simpler system should have the least headway, and the least delays due to switching etc, it has no flexibility. Thus, if a train breaks down, a passenger jumps on the tracks, a fire, etc, it is very difficult to route around the problem. The current system is packed to the gills during rush hour, and any problem at one station reverberates through the system for a long time: sometimes hours. It is especially problematic because everything is routed through a few stations downtown, and so you only have to close one of those stations to create a mess.

by SJE on Jan 24, 2011 5:41 pm • linkreport

surface transit routes, including streetcars don't have near the capacity. At best, light rail--not streetcars!!!!!!!!!!--can do 15,000 to 25,000 people/hour. To do that, it would have to be in separated right of way. Streetcar is better the buses, but would have to have much more frequency and greater train length than is currently planned.

Streetcar basically is for intra-jurisdiction transit, not metropolitan transit, hence the need to expand capacity of the heavy rail system.

That's why I've always been critical of the focus by DC on streetcars instead of DC also advocating for Metrorail improvements. While it is true that expanded streetcar planning and implementation can ease some pressures on Metrorail, the city's continued economic competitiveness with the central business district requires a focus on Metrorail as well. Dan T. seized on streetcars in a belief (not unjustifiable) that the region would never pull together the $ to do Metrorail capacity extension.

Note that expanding capacity in the current footprint is a somewhat different issue from extending capacity by extending the footprint of the system outward.

by Richard Layman on Jan 24, 2011 6:28 pm • linkreport

It's very easy to increase capacity for cheap.

1) Remove seats, like MBTAs "big red" standing room only cars.

2)Increase headways. 2.5 minute is currently the best metro does. Mexico City, Moscow and others do 90 seconds with longer trains and older systems. Thats a huge boost in capacity.

by JJJJJ on Jan 24, 2011 7:17 pm • linkreport

It's somewhat of a myth that light rail costs more than heavy rail. NYC looked into replacing 2nd Ave Subway with light rail and found there would not be great savings....

by Anthony on Jan 24, 2011 9:57 pm • linkreport

@Richard Layman Streetcars can be progressively expanded as capacity needs increase for little in capital outlay. We can have many more 10,000 rider/hour streetcar lines (more than half the capacity of a metro line) for the $1 billion it would cost to build any tunnel. All the capacity bottlenecks are inside the dc/Arlington cbd - it is incredibly inefficient to use high capacity heavy rail to serve 3-5 mile trips. Just for comparison: in Stuttgart, which has a 120 mile heavy rail comparable to metro serving the suburbs but also an extensive light rail/streetcar system (60 miles) to serve the central city, ridership is about evenly split between the two systems (at about 400,000 a day each).

by egk on Jan 24, 2011 11:21 pm • linkreport

His case study is the BART extension to SFO, which uses an awkward wye alignment that cuts frequency in half for each of the legs and is very confusing for users, but it was a simple diagram that politicians liked - no matter how problematic it was in a technical sense.

I think you, and he, are misunderstanding why the stupid wye was built. Everyone knew it would suck. It was built anyway for two, purely political, reasons. The technically sensible solution would have been to run BART to an intermodal Millbrae-type station (although perhaps not exactly at the current Millbrae location), and to extend the SFO airtrain to connect to that intermodal station and take passengers to the terminal of their choice. This didn't happen because (1) the federal dollars that were used to build the BART extension wouldn't have been available for an extension of the SFO airtrain, and (2) SFO has more political clout and wanted to be the primary destination, much as CAHSR is being totally fucked up just in order to satisfy San Jose.

by David desJardins on Jan 25, 2011 12:02 am • linkreport

P.S. The other operational difficulty of the BART wye, that he doesn't mention, is that BART now runs lots of trains through SFO to Millbrae, and they each incur a delay of several minutes because the train operator has to walk to one end of the train to the other, when it reverses at Millbrae.

by David desJardins on Jan 25, 2011 12:03 am • linkreport

Oops, I mean "when it reverses at SFO". Wish I could edit these comments.

by David desJardins on Jan 25, 2011 12:03 am • linkreport

the federal dollars that were used to build the BART extension wouldn't have been available for an extension of the SFO airtrain

This is a large part of the problem - Federal involvement in what are essentially local problems. Better to cut Federal taxes and subsidies and shift the burden to the localities that will benefit instead of all taxpayers.

by Chuck Coleman on Jan 25, 2011 6:48 am • linkreport

Agreed that it may be cheaper to build out an extensive light rail and BRT system, but keep in mind that the problem will now (and in the future) be core capacity. Ultimately, even with the growth of Tyson's and other surrounding cities, the bulk of the traffic is going towards DC. Maybe the logical expansion then is to start expanding stations to accommodate 12-car trains, rather than the eight they do now.

Food for thought.

by varun on Jan 25, 2011 8:21 am • linkreport

@David desJardins,

I don't think Walker was talking about the political sausage-making that resulted in the current SFO-BART arrangement, just commenting on the operations and the problem of that kind of political interference into an area where technical expertise ought to trump those more petty things.

The point is that the wye is a compromise, a result of a political process that ignores very real advice from transportation professionals. I think Walker uses it not so much to illustrate the process but the result. If you have a chance to watch the video that accompanies that slideshow, I'd highly recommend it.

by Alex B. on Jan 25, 2011 9:05 am • linkreport

The idea of the "light yellow" or "light green" connecting to the area near the existing Navy Yard stop via new flying junctions is a nice idea due to the presence of the ballpark there. Allowing a single-seat ride into Virginia would help disperse some of the crowding and relieve the pressure at L'Enfant Plaza. I suppose the IDEAL way to do this would be to expand the Navy Yard stop into a four-track station using two island platforms (similar to express stops in New York) and to put the "light" color trains on the outside platforms. They could then either skip Waterfront or use the same configuration there before routing the trains over the river. Come to think of it, I suppose a better design might be a four-track, THREE-platform design similar to the IRT 7th Avenue Line's 34th Street stop. That way you could serve the Green Line with the existing platform and the "light" color with the outer platforms (reason why this is good discussed below).

Of course, I recognize the financial impracticability of either idea, as it would cost an immense amount to tear out the granite facing in Navy Yard for expansion. If you can't expand it, the nearby stop (shown in the "light yellow" map above) is probably the better option than interlining through there. The reason is the same as the one WMATA used at RFK when they rejected the idea of running special trains using the link to the Red Line west of McPherson Square--when you have a congestion-generating source (the ballpark) feeding a single platform, it's more efficient if all the trains go to the same place, as people will then just board the first train that arrives instead of jamming the platform waiting for the "right" train. That's why the three-platform design can help, as it separates the traffic for the different trains. Since that design is financially unfeasible, having another nearby stop is the next-best alternative. Sure, some people will be confused, but some people are ALWAYS confused. 95% of the people using the subway to go to and from the ballpark would learn pretty quickly which stop to use.

The big thing that WMATA ought to consider that would improve efficiency in a different way, and cost a lot less, is the construction of either more pocket tracks or more sidings. (When I say "sidings" I mean the same idea as a pocket track only to the outside, rather than between the tracks. I don't know if that's the "correct" term.) If you consider the Orange Line, for example, there is no pocket track east of West Falls Church (a three-track station) until you get to a point east of Stadium-Armory. That's bad. It means there's nowhere to shove a disabled train out of the way, especially during rush hour (unless you count the Red Line connector tunnel), and it means that any time there's a problem with a train, delays cascade down both lines. The folks who designed the system 40+ years ago didn't think trains would break down and didn't anticipate door problems. Providing more options to store trains out of the way wouldn't SOLVE all problems with the system, but it would certainly allow some level of MITIGATION of an all-too-common problem with the way things currently operate.

With respect to the idea of running tunnels parallel to existing ones, one thing that might be desirable in that scenario is to have one of the trains make fewer stops, rather than echoing the existing stops on both lines (see the separated Yellow/Green map shown above, where they all make the same stops). In theory, that's a way of constructing the express trains so many of us have long desired. The "separated Blue" map above is an example where the Blue line would have 10 stops across town whilst the Orange would have 14 before the lines meet again.

by Rich on Jan 25, 2011 9:17 am • linkreport

BTW, two other thoughts:

(1) I cited the ballpark in my prior comment as an example of a good aspect of the "light yellow" or "light green," but I hope nobody misunderstands me as saying that ballpark service should be THE reason for those. The ballpark is in use perhaps 85 to 90 nights per year (81 Nationals games plus perhaps a few other events like the odd concert here and there or the occasional college game that draws a smaller crowd). So by itself, ballpark traffic isn't sufficient to support the service, but it's still a major source of business in that part of the system.

(2) Regarding comments others have made about the Pentagon: Don't forget that the Pentagon is also a major destination, perhaps the most significant destination, on the very successful slugging system along Shirley Highway in Northern Virginia. A lot of people who slug ride to the Pentagon and then take the Metrorail to their final destinations simply because so many of the slug drivers are heading for the Pentagon. There are a good number of slug lines downtown, true, but the numbers there are a lot smaller than in the Pentagon south car park (the "Carpool Staging Area" referred to on the big green signs on I-395). It's easy to look at the bus terminal and the subway stop, and they're vital, but the Pentagon is in many ways an overall transportation hub that isn't going away any time soon.

by Rich on Jan 25, 2011 9:29 am • linkreport

I'd love to see a somewhat new section to GGW blog site in the form of some permanent documents that are occasionally updated.

This post is a good example, there should be a list of items that we are pushing for METRO, which we consider "low hanging fruit"

I'd think longer 8 car trains would be #1, cheapest, fastest and easiest improvement. #2 longtitunal cars

Somewhere in top 10 I'd like to add expanding the width of the busiest METRO centers. I could be totally wrong but it doesn't seem that expensive.

If Metro Center had a center walkway where the doors opened to the LEFT and everyone exited, and then the doors to the RIGHT opened and everyone entered, it would be a huge help. A lot of high capacity airport trains use this model.

by Mike D on Jan 25, 2011 10:18 am • linkreport

The point is that the wye is a compromise, a result of a political process that ignores very real advice from transportation professionals.

My point is that they didn't ignore good design because they thought they knew better. They ignored good design because their goal was to get as much money as possible to build the thing and they didn't give a damn how well it would actually work.

by David desJardins on Jan 25, 2011 10:59 am • linkreport

Once it hits "the Heights", run the Yellow Line up 13th Street/Georgia Avenue and up into Maryland. That can bring a metro stop to the Walmart planned at Missouri/Georgia Aves., as well as all the development planned for Walter Reed. If well-planned, it can also serve Petworth (Sherman Circle area and above), 16th Street Heights, Brightwood, Crestwood and Shepherd Park neighborhoods.

by Swededc on Jan 25, 2011 5:34 pm • linkreport

This is a great conversation and I'm glad GGW provides the space and platform for it.

That said, I think we are beginning to understand that Metro is not just a DC system or an Arlington system but affects every jurisdiction that it touches. We will soon have serious capacity issues as well as a disjointed building strategy. We will need a separate blue line, this should not just be the District's problem. The Silver line probably shouldn't be 20 stops from Metro Center. How do we convince these jurisdictions (including the federales) that the investment in the expansion of Metro is in their own best interest?

by Randall M. on Jan 25, 2011 6:59 pm • linkreport

Hong Kong's MTR crams 2,500 passengers onto each 8-car train, using cars slightly shorter than Metrorail's. Even the standing-room-only estimates for longitudinal seating on WMATA's Kawasaki 7000s manages 1,500 passengers. Now, I know that we Americans are fat, wear big puffy coats, and like personal space so that we can sit and read our broadsheet WaPo while slobbering over our fries (oh wait, not on Metro) -- but surely we could continue to squeeze more capacity out of existing operations before building new tunnels and new stations everywhere. Matt pointed out some potential rolling stock enhancements before.

by Payton on Jan 26, 2011 1:25 am • linkreport

10 car trains should be practical at minimal expense. It only requires a good corridor connexion between the first and last pairs of cars on an 8 car train (same applies to an 8 car train where the current limit is 6. First and lst cars stop in the tunnel, or off the platform ends on open sections, and doors on end cars are not opened. CCTV screens and starting signals need to be duplicated close to the cabs (NOT replaced).This improves capacity 25% for 10 car trains, 33 1/3% for 8 car trains.
The Dulles Airport line will be far more important than the Vienna/Fairfax line, and the Orange line trains should run to Dulles. The Vienna/Fairfax trains should turn at Rosslyn, with the Dulles trains skipping all stations between East Falls Church (interchange) and Rosslyn (interchange).
The two branches off the Yellow Line - King-Huntingdon, and Pentagon-Waterfront-Union would be better as Light Rail feeder and distribution lines, respectively. WRD is correct in that it all comes down to Dollars, and you can get about 10 miles of light rail for the same cash as 1 miles of tunnel, with up to 50% capacity - though 20% will often be all that is needed. WMATA - or whoever is to run the new streetcar/LRV lines should take a look at the newest Budapest streetcars/LRVs.

by Dudley Horscroft on Jan 26, 2011 4:29 am • linkreport

Dudley Horscroft's comment provoked a question in my mind for anyone who knows. He raises an interesting point about the idea of a 10-car train if walking between the cars is allowed. But would that sort of thing require altering the train schedules (yes, I know the schedules are meaningless in practice) because of the required headways? That is, if you require a certain distance between trains, doesn't it follow that a longer train would then affect the timing of the next train in order to maintain that distance? The real difficulty in this respect would involve the shared-track sections where both lines' trains have to be timed properly with respect to each other.

by Rich on Jan 26, 2011 9:38 am • linkreport

@ Dudley Horscroft

What about

1 ADA issues

2 emeregncy/train has to be offloaded

3 crowded trains its hard enough to get out from the middle of a crowded car.

Would be very hard for people with bagadge, people with children or seniors to get from the first/last car to the one next to it and then out. They already ave problems when a door does not open and people have to run to the next door.

4 someone falling between cars

by kk on Jan 26, 2011 5:17 pm • linkreport

I am equally skeptical that 10-car trains in 8-car stations would actually add capacity. You need longer dwell times for loading and unloading, especially when the trains are crowded, which of course they will be at the peak times when it matters.

by David desJardins on Jan 27, 2011 12:52 am • linkreport

@Dudley @David desJ

David, great point, 10 cars won't work. They'd only work when the 8 cars are empty enough such that you would not need them. Dudley Oh well, it was an good out of the box idea.

by Mike D on Jan 27, 2011 10:36 am • linkreport

10 car trains is not a realisitic option. All of the track geometry (siding lengths, space between switches, yard capacity, etc.) is based on a max of 8 cars.

Metro's options for adding capacity via rolling stock are to:

1) Purchase more cars, run more 8 car trains
2) Reconfigure the seating in cars to add more standing room and thus more passenger capacity
3) Purchase new cars with more doors, which will speed boarding and alighting, thus reducing station dwell times and enabling more frequent service.

by Alex B. on Jan 27, 2011 10:48 am • linkreport

Cars with more standing room would be the cheapest and fastest capacity improvement once every train has 8 cars.

by PeakVT on Jan 27, 2011 10:52 am • linkreport

Metro needs to buy fully articulated cars in either groups of two or even better groups of four so that you could put two together for an eight car train. It would allow for load balancing while travelling between stations and provide for some extra passenger space.

by NikolasM on Jan 27, 2011 12:49 pm • linkreport

I'm sad there's never been any official proposal to build a line between Tysons and Bethesda. I would think that linking two major commercial centers like that would be a major benefit to the region.

by Andrew L. on Jan 27, 2011 2:38 pm • linkreport

Thanks for the comments.
@ Rich - I doubt that the running tracks and distances between signals, which are what counts, are set so that 10 car trains cannot be operated.
@kk 1 No ADA issues. No problem operating wheelchairs, etc, through corridor connexions.
2 No problems with emergency unloading any more than now, if train stops only part in station.
3 Unlikely people with baggage, etc, would want to go to end car unless they were going to an end station where there would be no crowding.
4 Corridor connexions prevent people falling between cars. Normal designs, just as if you were walking a couple of cars to get to the buffet car.
@ David, Mike D - People only wanting to go a couple of stations won't go to the end cars, only people wanting to go long distances will go there. And they will make their way back to the next to end cars in plenty of time so as not to increase dwell time.
@Alex B, PeakVT Cutting additional doors in the esisting stock may help. Replacing transverse seats by longitudinal may help, those experiments indicate the additional capacity is very low. You may be right about siding length, but if cars are now two car sets there should be no problem in remarshalling one end set to a separate siding. But if addional cars are required, then so are more sidings, which can take 10 car trains.
@NicholasM - 8 car train made up of 4 x 2 car units means 6 spare driving cabs - waste space. For a start remodel the existing stock into 40 car or 8 car units.

by Dudley Horscroft on Jan 28, 2011 7:42 am • linkreport

And they will make their way back to the next to end cars in plenty of time so as not to increase dwell time.

No, they just won't. We have empirical data about how people behave. You also have to get all of the new riders on and have them somehow filter through the standing-room crowd to get to the empty spaces in the inaccessible cars. There's no possible way this could not slow loading and unloading.

by David desJardins on Jan 28, 2011 10:56 am • linkreport

So I'm posting here over a year after this blog post was originally entered so I'm kinda late to the party. I thought I might chime in though anyway. I'm all for Metro expansion (and through heavy rail tunnels of course) but one thing that I would like to see is a Columbia Road N.W. Subway. This route was part of the intial 1965 Metro Route plan as a way to reach Columbia Heights. It was taken out in order to build what's now the Blue and Orange Lines through Southwest and near Southeast. It was determined that the neighborhoods served by this potential route, then white working class, were not those that the system was being built for. Ultimately, Columbia Heights was included on the Metro when African American community leaders pushed for the Green Line, which bypassed Columbia Road completely.

Because of this, Adams-Morgan never received Metro coverage (at least not direct coverage) and one of the densest areas of D.C. remains without a Metro station to this day. Of all the potential Metro expansion plans, none talk about expanding to Adams-Morgan or reviving the original Columbia Road route, which surprises me somewhat. Every time I walk through that area, I am struck by how urban and how dense it is (and yet how incovenient it is from the perspective of Metro rail transit).

I'm all in favor of the proposed expansions I see on your maps (especially the proposed M Street Subway and increased Capitol Hill coverage). I think though that a subway should be constructed linking Adams-Morgan (even if it means constructing a two stop route linking Dupont Circle and Columbia Heights stations). Another idea I had comes from your map with a separate proposed Longfellow Station on a rerouted Blue Line. I assume from the map that this stops at around 18th Street N.W. If that were to be constructed, I would propose building a new line up to Adams-Morgan underneath 18th Street N.W. It would have stops at Florida Avenue and Columbia Road. It would then cut up Columbia Road and connect at Columbia Heights. I would propose adding a station at 16th Street N.W.

Another alternative new route I would imagine would have a line underneath Columbia Road turn up 16th Street N.W., have an additional Mount Pleasant stop, connect with Walter Reed Medical Center, and then connect back with the Green Line (I'm thinking Fort Totten or Georgia Avenue).

by SoCalLiberal on Feb 4, 2012 2:25 am • linkreport

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