The Regional Connector and Network Coherence
The Regional Connector just opened in Los Angeles. This is a short, expensive tunnel permitting through-running for the city’s main light rail lines, linking the A Line (formerly Blue) with the half of L (formerly Gold) to Pasadena and Azusa and the E (formerly Expo) with the half of the L to East Los Angeles. It’s a welcome development and I only regret that this line cost, in 2022 dollars, $660 million per km. The broader question about the line, though, is that of line pairing and network coherence.
Network coherence is a nebulous concept. I can best define it as “it looks reasonable on a map,” but then the number of railfan crayons that violate coherence principles is so large that it has to be defined more precisely. Usually I talk about it in two concrete ways: a rapid transit network should avoid reverse-branching and tangential lines.
But there are some more concerns, which are less obvious than those two, and also appropriate to violate in some cases. My previous post on New York alludes to the principle of consistency of local and express trains, which is good to aspire to but may conflict with other priorities. In fact, the current pattern in Los Angeles is coherent: trains go north-south on the new A Line or east-west on the new E Line; the question, posed to me by a supporter (thank you!), is whether it should be. I think this is right, but it’s not obvious (in fact it wasn’t to the reader who posed this question).
The issue is that simple coherence – lines from the south should go north and not east, express trains on one side should go through city center and then be express on the other side, and so on – is a good starting point. But there may be other concerns at play. When SEPTA opened the Center City Commuter Connection in the 1980s, it relabeled its commuter rail lines R1 through R8, skipping R4, pairing each branch on the former Pennsylvania Railroad side with one on the Reading side; the resulting map, for which this was an early plan, was not at all coherent and featured self-intersecting lines, but it matched the lines based on expected ridership and railyard locations.
The New York City Subway, likewise, has some pairings that only make sense in light of railyards. The R train shares local tracks in Manhattan with the W train, but in Queens it goes to the Queens Boulevard Line whereas the N shares tracks with the W to Astoria, because the Queens Boulevard Line has a yard at the end and the Astoria Line does not, and the N has a yard at the Brooklyn end of Coney Island whereas the R does not at Bay Ridge; the R is the longest all-local line in the system and railfans periodically propose to switch it with the N in Queens, but the railyard issue makes it problematic in the current situation.
Matching branches by ridership, though, runs into the problem of inconsistent headways on the trunk. A light rail line running every eight minutes can share a tunnel with another light rail line running every eight, but if one of them runs every six minutes, they will run into each other on the shared section. This problem is magnified if both the shared section and the branches are long, which is usually the case in New York; thankfully, in Los Angeles the shared section is short enough that optimizing on it is less important. At most, it’s possibly to match branches by ridership if the train lengths can be made different.
The final concern that may lead to violations of coherence is origin-and-destination ridership patterns; I think this is what my reader had in mind when querying it. Such patterns may be ethnic – there’s a notable bump in ridership between Anacostia and Columbia Heights on the Washington Metro, and it’s likely that such patterns also exist elsewhere in cities that just don’t track O&D pairings, like New York with its internal Chinatown buses. They may even be classed, in the sense that wealthier Americans are likelier to be working in city center, but on the whole, rich and poor people are mostly traveling to the same places. They may be sporadic – a university may be driving ridership enough that there could be connections to either places students want to go or (for commuter universities like UBC) where students live.
O&D pairings like this should, as a rule, never drive infrastructure decisions. These patterns are too fleeting – for example, Columbia Heights’ gentrification is so rapid that the links with Anacostia are unlikely to last for more than a generation. However, it’s not always bad to look at them when making decisions on service for a given infrastructure network.
The issue, though, is that there’s no real compulsion to connect Long Beach with East Los Angeles or Santa Monica with Pasadena and Azusa. The commute data doesn’t suggest special links (which, to be fair, it also doesn’t in Washington). I am not aware of any other big pattern that would create such ridership. So it’s something that I think Metro should have looked at (and probably did), but ultimately made the right decision on.
Pedestrian Observations 
The New York City Subway, likewise, has some pairings that only make sense in light of railyards….
A few N trains run to or from 96th Street and Second Ave. Most of the day the N train runs express in Manhattan even though they call it a Broadway Local. Weekdays when the W is running.
They make sense in terms of shoveling people in and out of Queensboro Plaza or Lexington and 53rd. Run more trains to Queens Blvd through the 60th Street tunnel they don’t go to Queensboro Plaza. Run more trains through 60th Street Tunnel to Queens Blvd., there are less trains running through the 53rd Street tunnel and less of them at 53rd and Lex. Finagling things is likely why there are E trains that use Hillside Ave. instead of Archer Ave and a W train or two that ventures into Brooklyn.
Yeah, the special trains that run weirdly, like the 2 trains from 148th, the Es from Hillside, and so on are always fun kludges.
LA’s regions are so isolated compared to many cities that effectively mapping transit on top of current connections gets hard for long trips. In explaining the city to people who have not lived there, I typically call it a city ‘made of small towns’.
The light rail providing a connection across the metro which runs on a frictionless set schedule and with known tempo is something that has not existed since the Pacific Electric closed. A commute from Azusa to anywhere out towards Santa Monica would be hellish on the highways, and an odyssey even on the sleepiest of weekends. Taking the new E all the way out to the sea is realistically too far for the average commuter, but it’s interesting how the line services journeys which might be considered ‘new’ in certain ways.
I get frustrated with Metro for being slow and plodding, but generally I find their current project set to be well-reasoned. Regional Connector + D Line Extension/Subway to the Sea + Sepulveda Pass are the three big ‘obvious projects’ in Los Angeles to provide a barebones skeleton of connectivity. With the city as sprawling and polycentric as it currently is, there is not much to do but to build the obvious lines and then do what is possible to encourage jobs and housing to follow that skeleton.
Pie-in-the-sky, I hope they one day pursue an effective ‘express’ method to get across the western city. Metrolink expansion southwest from downtown would be a beautiful thing to see, giving riders the option of a fast commute from OC/San Bernardino down to the sea. But, I’m not holding out hope.
Living in LA and having ridden each Metro Rail line and looked at each station up to Metro A Line’s Pasadena Station, I concur that LA Metro made the correct ridership decision on the new A & E line pairings. Former Gold Line riders from East LA will have to get used to transferring underground in Little Tokyo to reach LA Union Station and points North. I would like, however, the A & E lines to eventually reach 6-minute headways.
The next thing to fix is Flower-Washington Wye Junction. Hopefully, LA Metro can get CalTrans (Highways guys) to close the I-10 freeway entrance next to Flower-Washington Wye. Since the freeway entrance cuts in front of A & E Metro lines near the wye, it’s also a public safety matter that slightly limits Metro train frequency & schedule reliability. The second, far more expensive, fix is to build a short subway from Flower-Washington Wye to a point just north of Venice Blvd. In that manner, fewer automobiles would have frequent gate waits too.
What are your thoughts on the Inglewood APM?
Inglewood APM should be self-funded by the stadiums. It’s a drop in the bucket for them compared to improved access for their primary money-makers. The line is going to be under 2 miles long, not some megaproject.
If they were really thinking, they would reclaim portions of the parking for additional high value-add revenue drivers in time for the Olympics. Add some multi-story shopping options, additional food, or other entertainment amenities. The APM would pay for itself quickly.
> The next thing to fix is Flower-Washington Wye Junction.
It was kind of a lost opportunity when building the regional connector. The tunnel portal on flower street/ 11street is only ~4000 feet away from that intersection. If they had tunneled a bit farther they could have had the exit portals past the intersection instead.
> Hopefully, LA Metro can get CalTrans (Highways guys) to close the I-10 freeway entrance next to Flower-Washington Wye.
I don’t think that is the major bottleneck. I thought the problem was left turning cars on Flower Street onto Washington Boulevard. The other problem is that trains going to Long Beach (making the left turn south bound) block trains going to Santa Monica. Potentially they could add a third waiting track to separate the south bound movements.
Thanks Alon for writing this post! I reached out to you about this, and I might be who you are referring to here. I’m based in NYC, so I don’t have as good of a sense of LA, but what stands out to me is that you want to maximize the number of one-trip to try to convert as many people from cars to trains as possible.
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From a superficial analysis, it seems like you want to connect the two most popular branches together to maximize the number of one-seat trips. In this case, since the Pasadena line is longer and wealthier, there may be more people who are commuting onto the Santa Monica line, which seems to have many more offices than the Long Beach line. By connecting your two most used lines together, you are creating more trips than connecting a more used line to a less used line. It is an extremely long line, and it is not as intuitive as a north-south/east-west connection, but it does seem like if you are trying to create a shift in transportation patterns in LA, this configuration would more effectively support that shift. Conversely, LA is so big that the idea of commuting from Pasadena to Culver City or Santa Monica is already a no-go, and the idea of a 1 hour subway ride isn’t very likely as is.
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The more surprising thing for me is that in digging into this question, I have not seen a single analysis from the LA Metro about the pro’s and con’s of the two configurations. So often there is a public analysis that describes competiting options, but there was nothing here. Steve Hymon from the source acknowledges that the line could be altered in its layout in a 2020 post, but that no analysis has been shared since then: https://thesource.metro.net/2020/02/19/la-metro-quietly-trying-to-do-something-never-before-tried-in-building-the-regional-connector/
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From the perspective of ethical urban planning, maybe this configuration is the best. Similar to what you noted in Washington DC with Columbia Heights, this configuration will definitely spur development in East LA. Is this a good thing? Urbanization follows transit, and if a more developed / more gentrified East LA is a good thing, this configuration will further that goal. As you noted, these decisions should be thought of on a 25 year timeline, not say a 5 year timeline, and using through-running to reshape cities may be effective here. Thanks for sharing your thoughts!
FYI historically the old Blue Line (Los Angeles to Long Beach) had higher ridership then the Expo Line (Los Angeles to Santa Monica). In 2018, which is the last full figures before the Blue Line was shut down partially for rebuilds and construction, the Expo Line had 19.4 million annual riders and the Blue Line had 19.8 million. The highest numbers for the Blue Line were almost 29 million in 2012, while 2018 was the highest point for the Expo line, so perhaps the Expo line ridership will continue to grow, but we could also hope for a reverse in the decline in Blue Line ridership with the new connection.
https://en.wikipedia.org/wiki/E_Line_(Los_Angeles_Metro)
https://en.wikipedia.org/wiki/A_Line_(Los_Angeles_Metro)
Thanks Joseph for sharing! Yes, so I think that is the really interesting question – should a subway system try to optimize for supporting and extending the highest usage, or should it aim to better distribute higher and lower usage? My hunch at the moment is that with this configuration, there will be more transfers between the A and the E line with this configuration than there would be if the lines switched, but that if you are looking to grow ridership and develop East LA and the Long Beach line, this will better create that impact over say the next 10-20 years, relative to the alternative of running East LA line to Long Beach. An alternative could be to run both lines in both directions, but it seems that there is a strong commitment to just having each line run in one direction.
FYI, Metro’s 2020 analysis of passenger O-D data, network simplicity, headway consistency, and operating costs for the three operations alternatives they identified here:
https://boardagendas.metro.net/board-report/2020-0613/
Thanks for sharing this document! This is what I had been looking for and couldn’t find. The heart of it seems to be that this is slightly easier to manage operationally, as well as being the Locally Preferred Alternative. While the LPA is cited multiple times in the article, there is no discussion of why it is the LPA. There is some underlying preference here that this configuration better serves some subset of the riders, but it is interesting that it is not named. I am curious to what extent external forces may have influenced this decision – for example, there has been a strong push to redevelop East LA, and this configuration might be the Locally Preferred Altrenative of developers who want to develop the area and provide these one-seat rides to say the growing office/tech hubs in Santa Monica and Culver City.
One fundamental thing to understand about US “public” “planning” is that once “alternatives” are presented for “discussion”, it’s at least five years too late to change anything.
Generally this shit is cast in stone — invariably in the shittiest, most expensive and least useful fashion — in some sort of sekrit agency-internal “Project Study Report” that is prepared by consultants for purposes of private agency masturbation needs, as well as the overriding need to feed the consultants.
Then total strawman “alternatives” are dreamed up. These are either totally unrealistic, or they are based on something potentially OK but mercilessly sandbagged by bought-and-paid-for consultant wankers so that there is no alternative to what they’ve already determined to do.
It is only a this stage that the list of “alternatives” along with a Locally Preferrered Alternative are presented by anybody not directly on the take. This is either for agency board “discussion and approval” (which means a rubber stamp, no question at all, and lots of back-patting on staff for the hard work they’ve put into developing so many good choices all of which meet Community Needs to varying degrees, and are Responsive to Concerns, but the LPA really does hit the sweet spot, the motion is approved, next agenda item) or it’s for some Potemkin “Draft Environmental Impact Study”, in which case a bunch of losers from the public (hey, this was once me!) get to waste huge amounts of time reading and responding to the bullshit alternatives and bullshit obvious sandbagging, before the Locally Preferred Alternative is approved without change in the Final Environmental Impact Statement. So many years of so many full-time consultants. So many many billable hours!
Maybe the LA Connector alterantive is OK. Sometimes it happens, by pure accident. But not because there was any serious study or any real alternative analysis at any time. That’s just not how we do things around here. Forget it, Jake. It’s Chinatown.
The good news: Metro can always change the operations plan based on actual observed and try out one of the other operations alternatives!
Is this specific type of infrastructure project–enhancing network coherence by joining two formerly disconnected systems and then reshuffling the services–something that’s discussed in the literature, perhaps to the point that it has a name? That’s at least two examples in the US; the North-South Rail Link, if it’s ever built, would be a third, and I think it’s at least somewhat different from Crossrail or the Paris RER. The tunnels built as a precursor to the Zürich S-Bahn may qualify as another example.
It’s called “The blindingly obvious thing to do, duh, what the hell is wrong with you, were you dropped on the head as an infant?”
PS there are scores (Over a hundred? Perhaps?) of examples world-wide.
I’m sure there are. Lots of things are the obvious Right Thing to do, but it usually takes more than that to spend a couple hundred million on a years-long infrastructure project, with all the system-wide operational changes to (hopefully) take advantage of the improved infrastructure. Vuchic published extensively on the Center City project in the mid-1980s, for example, but literature that took a broader view and compared the approach in different countries would be interesting.
Regardless, how relevant is this to the retarded English-speaking world anyway?
Do they need a translation for “Durchmesserlinie” or “passante ferroviario”or whatever, given that there are only a small handful of potential cases? Outside of London, New York, Boston, Chicago, Denver (!!!!!!), Montréal (!!!!) how many CBDs with multiple terminal stations in English-speaking countries are there to connect these days? Yes, there are a number of terminal stations that might be amended and extended with through-running tracks, but again, a handful, Anglosphere-wide, and some of those are even in progress, in various moderately to severely brain-damaged fashions.
It’s a better use of one’s time to knock oneself out Englishing “Integraler Taktfahnplan” or “Tarifverbund”.
Or “Klimakatastrophe”
I’m genuinely sorry that I brought it up.
I apologize. But really, the word for it in English is “Boston North—South Rail Link”. That’s pretty much all that’s on the table, even as crayon.
You can point at the scores of any other examples in the world and call them “the new cross-city rail tunnel in Leipzig” or “the new cross-city rail tunnel in Milan” or “the three[!!!] parallel cross-city rail tunnels in Madrid” or “the new cross-city rail line in Prague” or “the cross-city rail tunnel in Oslo” or “the ridiculous number of different ways different rail lines on one side of Tokyo connect through subway tunnels to rail lines on the other side of Tokyo” or “the two different tunnels that connect rail lines approaching Zürich from different directions to the trunk routes heading west” or “the way nearly all trains to the central station in Sydney run in tunnels that either loop around under the CBD or run under the CBD and connect to the line running north” or “the rail tunnel in Philadephia that all the sad pathetic Septic trains use” but is there need for a special term to discuss this one single case? “The thing that in a better world would have been done in the 1930s, and we might be talking about duplicating today because it’s groaning at the seams”
I do think it would be worth it for LA Metro to have a new L line which would connect the Westside and Santa Monica, using the Western Branch of the E line, with at least some segment of the original L line to Pasadena. The current E line just barely misses Union Station, and since that is physically possible with the current rail alignment, the Westside should have a one-seat ride to LAUS.