Stadtbahn Systems

I made an off-hand remark about subway-surface systems, called Stadtbahn in German (as is, confusingly, the fully grade-separated east-west Berlin S-Bahn line), regarding a small three-line single-tail network that Brooklyn could build. I also talked about it in a little more detail last year. I want to go more deeply into this now. It’s a public transportation typology that’s almost nonexistent outside Germany and Belgium; Tel Aviv is building one line, and the US has three but two of those are from more than 100 years ago. But there are interesting examples of good places to use this technology elsewhere, especially elsewhere in Europe.

What is the Stadtbahn?

The Stadtbahn (“city rail”), or the subway-surface line in US usage, is an urban line running light rail vehicles, with grade separation in city center and street running outside city center. All examples I know of are in fact underground in city center, but elevated lines or lines running in private rights-of-way could qualify too, and in Cologne, there’s a semi-example over a bridge dropping to the surface at both ends.

It’s best illustrated as a 2*2 grid:

 Slow in centerFast in center
Slow in outlying areasTramwayStadtbahn
Fast in outlying areasTram-trainRapid transit

The terms fast and slow are relative to general traffic, so a mixed-traffic bus in a low-density city that averages 30 km/h is slow whereas the Paris Métro, which averages 25 km/h, is fast; the speed in km/h may be higher on the bus, but the speed in destinations accessed per hour is incomparably higher on the Métro.

The tram-train is confusingly also called Stadtbahn in Germany, for example in Karlsruhe; this is nearly every light rail built in North America. It is not the topic of this post.

What is the purpose of the Stadtbahn?

Historically, Stadtbahn systems evolved out of pure surface tramways. City center congestion made the streetcars too slow, so transit agencies put the most congested segments underground. This goes back to Boston in 1897 with the Tremont Street Subway and Philadelphia in 1906 with the Subway-Surface Lines. The contrast both in that era and in the era of Stadtbahn construction in Germany from the 1960s to the 80s is with pure subways, which are faster but cost more because the entire route must be underground.

Stadtbahns always employ surface branching. This is for two reasons. First, there’s more capacity underground than on the surface, so the higher-capacity rapid transit segment branches to multiple lower-capacity tramways to permit high throughput. And second, there’s generally less demand on the outer segments than in the center – lines with very strong demand all the way tend to turn into full subways.

This is therefore especially useful for cities that are not huge. In a city the size of Cologne or Stuttgart or Hanover, there isn’t and will never be demand for a rapid transit system with good citywide coverage. Instead, there is something like a sector principle. For example, in Cologne, the Deutz side of the city, on the right bank of the Rhine, has service to city center on the S-Bahn, on tramway lines over the Deutzer Bridge branching on the surface, and on tramway lines over the Mülheimer and Severin Bridges feeding into the north-south ring Stadtbahn. Smaller cities have simpler systems – Hanover for has three underground trunk lines meeting at one central station, and Dortmund has three meeting in a Soviet triangle. This maintains good coverage even without the budget for many rapid transit lines.

Where are Stadtbahns appropriate?

Cities should consider this technology in the following cases:

  • The city should not be too big. Tel Aviv is too big for this, and people in Israel are starting to recognize this fact and, in addition to the under-construction three-line Stadtbahn system are proposing a larger-scale three-line fully grade-separated metro system. If the city is big enough, then a full metro system is justified.
  • There should be a definitive city center for substantial traffic to funnel to. The purpose of the Stadtbahn is to have comparable throughput to that of a metro, albeit with shorter trains.
  • There should be wide swaths of sectors of the city where having multiple parallel lines is valuable. This, for example, is the case in cities that are not exceptionally dense and cannot expect transit-oriented development to completely saturate one metro corridor.
  • The street network should not be too gridded, because then the sector-based branching is more awkward, and the combination of rapid transit to city center and a surface transit grid can be powerful, as in Toronto.
  • There should be too much city center congestion for a pure surface system to work, for example if most streets are very narrow and traffic funnels to the few streets that can use

These circumstances are all common to German urbanism: city centers here are strong, but residential density peaks at 15,000/km^2 or thereabouts in near-center neighborhoods and drops to 3,000-6,000/km^2 farther out. Moreover, Germany lacks huge cities, and of the largest four urban cores – Berlin, Hamburg, Munich, Frankfurt – three have full rapid transit systems. Finally, grids are absent here except at very small scale, as in Mannheim.

However, these are not unique features to Germany. They’re common around Europe. European cities are not very big, and the only ones that can genuinely fill any subway line with transit-oriented development are a handful of very big, very rich ones like London and Paris. Even Stockholm and Munich have to be parsimonious; they have have full metro systems with branching.

The French way of building rapid transit does not employ the Stadtbahn, and perhaps it should. In a city the size of Bordeaux or Nice, putting a tramway underground in city center and then constructing new branches to expand access would improve coverage a lot.

This is likely also the case in Italian cities below the size class of Milan or Rome. Many of these cities are centered around Renaissance cores with very narrow streets, which are nonetheless auto-centric with impossibly narrow sidewalks, Italy having nearly the highest car ownership in Europe. Finding one to three good corridors for a subway and then constructing tramways funneling into them would do a lot to speed up public transit in those cities. Bologna, for example, is planning a pure surface tramway, but grade-separated construction in the historic center would permit trams to have decent coverage there without having to slow down to walking speed.

Are there good examples outside Europe?

Yes! From my original post from 2016, here is one proposal for New York:

The B41 could be a tramway going between City Hall and Kings Plaza, using two dedicated lanes of the Brooklyn Bridge. In that case, the line would effectively act as subway-surface, or more accurately elevated-surface: a surface segment in Brooklyn, a grade-separated segment between Manhattan and Brooklyn. Subway-surface lines should branch, as all current examples do (e.g. Boston Green Line, Muni Metro, Frankfurt U-Bahn), because the subway component has much higher capacity than the surface components. This suggests one or two additional routes in Brooklyn, which do not have strong buses, but may turn into strong tramways because of the fast connection across the river to Manhattan. The first is toward Red Hook, which is not served by the subway and cut off from the rest of the city by the Gowanus Expressway. Unfortunately, there is no really strong corridor for it – the streets are not very wide, and the best for intermediate ridership in Cobble Hill and Carroll Gardens require additional twists to get into the core of Red Hook. Court Street might be the best compromise, but is annoyingly a block away from the F/G trains, almost but not quite meeting for a transfer. The second possible route is along Flushing Avenue toward the Navy Yard; it’s not a strong bus by itself, but the possibility of direct service to Manhattan, if a Flatbush tramway preexists, may justify it.

Note that this proposal is opportunistic: Brooklyn Bridge just happens to be there and point in the right direction for at least one strong surface route in Brooklyn, and conversely would connect too awkwardly to the subway. In a city the size of New York, Stadtbahn lines must be opportunistic – if the region intentionally builds new river crossings then they must carry the highest-capacity mode of transportation, which is rapid transit, not a light rail variant.

American cities smaller than New York are often very big by European standards, but also very decentralized. This hurts the Stadtbahn as a mode – it really only works for a monocentric city, because if there are multiple centers, then all but the primary one get slow transit. The Rhine-Ruhr notably uses the S-Bahn, which is rapid transit, to connect its various cities, and only run Stadtbahn service internally to each center, like Cologne or Dortmund.

There are a number of places in the United States where burying a light rail line in city center is advisable, but this is for the most part conversion of a tram-train to rapid transit, for examples in Portland and Dallas. The only example that come to mind of a decent Stadtbahn in the US that doesn’t already exist is Pittsburgh, converting the BRT system to rail.

Outside the United States, I get less certain. Canada is bad geography for a Stadtbahn because of its use of grid networks; Ottawa may be good for a Stadtbahn using the Confederation Line tunnel, but that’s probably it. Australia may be better, combining decently strong city centers with very low residential density; transit-oriented development potential there is very high, but it could plausibly come around multiple distinct corridors as well as regional rail stations. Melbourne’s tramways thus may be a candidate for Stadtbahn conversion.

In both East Asia and in the developing world, it’s likely best to just build full metros. East Asian cities are big and have high rates of housing construction (except Hong Kong). I can see a Stadtbahn succeed in Taichung, extending the under-construction Green Line on the surface and building intersecting lines, but that’s probably it. Kaohsiung already has a (very underused) subway, what I think is Daejeon’s best next corridor on top of Line 1 and the planned Line 2 is unusually bad for a Stadtbahn because the streets are too gridded west of the center, Daegu is too gridded as well.

A similar set of drawbacks is also true for the developing world. The urban population of the developing world tends to cluster in huge cities. Moreover, these cities tend to have high residential density but low city center job concentration; the Addis Ababa light rail is bad at serving people’s work trips because so few people work in the center. Finally, the developing world has high rates of increase in urbanization, which make future-proofing systems with higher capacity more valuable.

91 comments

  1. Nilo

    Some thoughts on places that might work for Stadtbahns.

    1. Camden, NJ over the Ben Franklin Bridge.

    2. Brazilian cities with around 2 million people in the urban area of less. Think of places people haven’t heard of like Vitória, Natal, and Florianópolis

    3. Madison, Wisconsin. People often talk about an S-Bahn here, but the geography seems well suited, perhaps better suited to a Stadtbahn. Main reason to prefer S-Bahn is the large amounts of legacy track.

    • Alon Levy

      Camden already has the PATCO connection…

      But yes, Madison could support a Stadtbahn, provided there’s enough congestion on the isthmus to justify it as opposed to pure tramway.

      • Nilo

        Yeah, but it only has two PATCO stations.. You could of course just have a local tramway system terminate at them for the forced transfer to Philadelphia, but the bridge connection doesn’t seem that hard in a functional country given the fact the bridge was built to carry tram tracks.

        • Eric2

          There already is a local rail system with forced transfer – NJT River Line.

          My pet idea for this region is build a connector between the PATCO tracks and SEPTA tracks in Chinatown, then run PATCO, River Line, and one or two more ROWs in NJ as SEPTA regional rail branches…

          • ckrueger99

            PATCO is an interesting contrast case study, a rapid transit line into Philadelphia via Camden where maybe Stadtbahn might have been more appropriate. It was originally planned to have three suburban branches, but only one was every built. That one works very well, but it’s just barely on the density level in the NJ suburbs to support frequent service. Those other, unbuilt branches (FYI, to Glassboro and Moorestown) would not have had the density it appears (but with TOD, who knows?).
            Meanwhile, in the city of Camden itself (can be thought of as a part of Philadelphia), PATCO serves no internal purpose, only connects one small, central part of Camden with Philly and the Camden County suburbs. It certainly feels like there is a racial element to this, with Camden city being majority black; the rest of the County, white.
            OTOH, the Philadelphia SEPTA Subway-Surface lines service nearly exclusively black neighborhoods in Southwest Philly.
            Given what we have in Camden, it seems the best opportunity for better coverage is to improve the intermodal bus-PATCO and tram-PATCO system at Broadway station.

          • Eric2

            ” It certainly feels like there is a racial element to this, with Camden city being majority black; the rest of the County, white.”

            I don’t think so – the Camden tunnel was built in the 1930s, while Camden only became mostly black in the 1970s or later. (From a quick Wikipediaing)

          • ckrueger99

            That’s true. And the suburban sector comes from the even older PRR-Reading Seashore Route ROW. So we end up with two rail services (PATCO and RiverLine) that make hardly any stops in the residential areas of Camden. If they had chosen a subway-surface configuration, we could have better coverage in the city, which wasn’t going to happen back in 1968. The selling feature of the PATCO line was its high-speed, i.e blasting through Camden without stopping.

      • Brendan Dawe

        Camden also has lots of other existing mainline branches that can go fast instead of street tramways

      • Harald Kliems

        I think Madison fails the “too much city center congestion for a pure surface system to work” criterion. As much as locals like to complain about traffic, actual congestion is (well, was, before COVID) pretty tame. If you look at a map of current bus boardings, you see how central the UW campus and the downtown core are for ridership: https://rpubs.com/vgXhc/metro_boardings
        We’re in the process of getting our first BRT line, and there’s also a network redesign study that has just started.

      • Michael Schaeffer

        Would you say that the proposed Project Connect in Austin could be considered a Stadtbahn?

  2. Brendan Dawe

    I suspect that the Granville-Hastings core of the Vancouver bus grid was a sort obvious ‘rubber stadtbahn’ if there were to be such a thing

    • Alon Levy

      Oh, as in going underneath Granville (or I guess a parallel street now), crossing False Creek, and then branching? Maybe… but the CP line is right there, and Vancouver is plausibly in the “everything can be redeveloped at high density if permitted” basket. There’s nobody living east of the line around King Edward and that could be some beautiful high-rises.

      • Brendan Dawe

        I’m guessing the CP Line you mean the line next to Arbutus? True, some beautiful high-rises up and down Arbutus to
        But I find myself inspired by the many-down-to-trunk-line pattern of the downtown-touching parts of the bus grid

        • Alon Levy

          Something I probably should have mentioned in the post re Toronto, also applicable for Vancouver, is that in the presence of a rapid transit line, closely parallel surface routes lose value. Oak for example is a weak north-south bus corridor. Granville… I guess?

          At the other end, I guess you could subway inner Hastings and then split, depending on whether we worry there’s enough demand to SFU to fill a subway.

  3. Gok (@Gok)

    Is this actually meaningfully cheaper to build than rapid transit today? If you’re going to get the tunneling equipment out anyway, surely the marginal cost of just digging further can’t be that much higher, especially since you’d need to do lots of surface level work to install rails, electrification, stations, etc.

    • Nilo

      Tramways in Paris display a significant cost discount compared to the equivalent amount of linear meters of metro.

    • threestationsquare

      The marginal cost of additional length of tunnel isn’t that high once you’ve started, but the marginal cost of each underground *station* is very high as each one has to be excavated individually. Surface stations are much cheaper.

      • Richard Gadsden

        This. The cost of a TBM is the biggest factor in the cost of a tunnel, so short tunnels can work out expensive per metre (lots of short tunnels are fine as you can move the TBM from one tunnel to the next), though most city-centre tunnels will be at least a couple of kilometres which is plenty to get reasonable use out of the TBM. Some smaller systems may be a pair of tunnels (one for each direction), excavated by the same TBM, going first one direction and then back the other way – takes longer but reduces the capital cost.

        But underground stations are much more expensive both to build and to operate than surface stations.

        A surface tram stop can be operated with no staff at all; an underground station requires a full-time staff presence to be able to conduct an emergency evacuation, to deter vandalism of the lifts and escalators and to notify maintenance if a lift or escalator fails. Underground stations also have more requirements in terms of cleaning, particularly because of fire risk.

        • df1982

          Most German U-Bahn stations have zero staff presence, whether they are above-ground or underground.

          • Nilo

            Was about to say that I’ve been on rapid transit stations in the US without staffing, though agencies here tend to be moving to staffed stations (primarily I think to provide the impression of safety).

          • Nilo

            Presumably people take the stairs up. Most American stations due to the painful cost of construction are rather old and very shallow.

        • Henry t

          What if we followed the Spanish practice of stations in the tunnel. Requires bigger tunnels, but overall should be cheaper. So long as stations are art and places that isn’t possible, but if we think of stations as a place to get out of right away then we don’t want them to look good. We just need something that says vandals, muggers and rapists will be caught so don’t bother, which can be done a lot cheaper.

  4. threestationsquare

    > It’s a public transportation typology that’s almost nonexistent outside Germany and Belgium
    Cities with stadtbahns (by your definition) outside Germany, Belgium, & the US include Addis Ababa, Alicante, Amsterdam (line 26), Barcelona (T5/T6), Den Haag, Granada, Kraków, Lille, Linz, Nice, Paris (T2 north from La Defense), Porto, Rouen, Toronto (509/510), Tuen Mun, Volgograd, and Wien. Within the US I’d also count Cleveland and Newark in addition to your three examples.
    > In a city the size of Bordeaux or Nice, putting a tramway underground in city center and then constructing new branches to expand access would improve coverage a lot.
    Nice did put a tramway underground in the city centre! It opened last December!
    > There are a number of places in the United States where burying a light rail line in city center is advisable, but this is for the most part conversion of a tram-train to rapid transit, for examples in Portland and Dallas. The only example that come to mind of a decent Stadtbahn in the US that doesn’t already exist is Pittsburgh, converting the BRT system to rail.
    Since the Pittsburgh BRT lines are already grade-separated outside the core, that still wouldn’t be a stadtbahn by your definition.

    Austin is voting on a stadtbahn proposal on Tuesday; the branching in the specific plan looks a bit weird but it overall seems like a reasonable typology there. There might also be a case for it with the Ballard and West Seattle lines in Seattle. New Orleans, Quebec City, Providence and Madison come to mind as other North American cities that might fit the specifications you mention here. Also Cincinnati has what could be part of a stadtbahn tunnel already constructed and sitting unused.

    • fjod

      Amsterdam line 26 isn’t meaningfully a Stadtbahn; it just has a tunnel in the middle so it can get under some water. It’s pretty classic light rail and isn’t grade separated in the centre. It was however de-scoped from a full metro line.

      Also I have always thought Birmingham (UK) would fit a Stadtbahn. It has a dense city centre and wide underused arterials through mid/low-density suburbs.

    • SB

      I think Pittsburgh Light Rail should be considered Stadtbahn because it has grade separated underground and elevated section and branching surface section.
      Also Pittsburgh doesn’t have (real) BRT yet. It has busways.
      South busway partly shares ROW with Light Rail.

      • threestationsquare

        Since Pittsburgh’s light rail is also largely grade-separated (or at least on dedicated right-of-way) further out as well as in the core, I think it’s “light metro”/”rapid transit” in Alon’s typology? Though there is a bit of street running on the red line in Beechview.

        Pittsburgh’s grade separated busways are far more “real” rapid transit than the typical “BRT” lanes that get used as parking for delivery trucks & cops and still require buses to wait at stoplights.

  5. Alex Cat3

    Would Newark be a good candidate for a stadtbahn? It already has an extremely minimal one, that is its subway line. Though the subway only has two branches, and the main one is entirely grade separated in the former bed of the Morris Canal, it also has an (extremely slow) street-running spur connecting Newark Penn with Newark Broad Street. Newark’s street network may be mostly gridded, but its bus system is radial, centered around Newark Penn and the former streetcar terminal. Although there is commuter rail– the NEC/Raritan Valley line and the Morris and Essex line, the lines miss important poor, dense neighborhoods like Irvington. Current ridership is likely not high enough to support anything more than BRT, but the city has a lot of potential for gentrification. Such a system would make no sense at NJ’s current sky-high construction costs, but perhaps if we could build at the cost of Paris, it would be a good idea?

    • adirondacker12800

      Morris and Essex line, the lines miss important poor, dense neighborhoods like Irvington.
      East Orange has had grade separated rail service to Broad Street in Newark and Hoboken for over 100 years and electric service since 1931. They take the bus. East Orange had another station at Grove Street. It was closed for lack of interest.

      Click to access T0021.pdf

    • threestationsquare

      The main line of the Newark City Subway is not entirely grade separated, I believe it waits at stoplights at three different intersections out near Silver Lake (example).

      Until the 1950s it had four street-running surface branches (Orange via Market St, Orange via Orange St, Central Ave, Bloomfield Ave; map) which could conceivably be restored. But those lines parallel the M&E; running regional rail trains more frequently with lower fares is likely a better investment for those destinations than tramways. Irvington is mostly in the wrong direction to use the subway.

      • adirondacker12800

        Let me check to if I understand what you are proposing. Get on the bus, transfer to the train and then get on another bus in downtown Newark. And the reverse on the trip back. Sounds great to me. How much longer will it take than just staying on the bus?

  6. df1982

    So by your reckoning is Seattle’s light rail a Stadtbahn or a light metro, since it’s fast (underground) in the core and pretty fast (at grade/elevated) in the periphery?

    What you’re proposing for the Brooklyn Bridge sounds a lot like the set-up with the streetcars there prior to the 1950s.

    And re. Australia: Sydney actually had something like a Stadbahn before 1961, with tramlines on the north shore going over the Harbour bridge and into an underground station in the CBD (Wynyard). This section of the line was designed to be converted to heavy rail, but when the trams were scrapped it was converted into roads instead, with a carpark taking over the station (Grrr…). A lot of fantasy rail plans involve restoring the second pair of tracks on the bridge to metro or light rail, but the official line is this wouldn’t meet modern operational standards (although I am dubious about that claim).

    There were also plans for a similar set-up in the Eastern Suburbs, using built but unused underground platforms at St. James and Central, but this was canned by the Labor government, which at the time was extremely pro-car. And now there are separate pipelines for metro and light rail construction, without much consideration for combining the modes.

    Melbourne has had plans to underground its CBD trams over the years, but they have never gone anywhere, and are probably politically unpalatable. In any case, I don’t think they would provide much bang-for-buck. The trams play a useful role in CBD circulation (the underground rail loop is useless for this purpose) and any rail lines going under should just be built to heavy rail standards, as indeed is presently being done under Swanson St.

    Brisbane is currently planning to build the somewhat misnomered Brisbane Metro, which looks a little bit like a Stadtbahn but with rubber tyres instead of rails, since they are re-purposing some of the city’s BRT lines for the project. The jury’s out on this though. For Adelaide and smaller cities (Gold Coast, Canberra, Newcastle, Wollongong), regular light rail would suffice. Perth is a possibility.

    • Eric2

      The basic idea unique to stadtbahn is “grade separation where it’s needed in the high frequency core, at grade in the low frequency branches”.

      Seattle isn’t entirely grade separated so it’s not a metro. It also doesn’t currently have branches, although it will soon get one, at which point it will qualify as stadtbahn. But it wouldn’t qualify now in any meaningful way, unless you want to say that the higher cross traffic levels in places like downtown make grade separation more urgent there.

      • Nilo

        IIRC Seattle has one at Grade segment to the south. It doesn’t really fit Alon’s typology here, but really what it is is a metro system with one odd at grade segment.

        • Eric2

          There are two segments, forming a significant fraction of the line. All the grade crossings must put a ceiling on headways, but Seattle isn’t big/dense enough for this to be a problem now. (And in the future the grade crossings will be on a branch, thus the system will have stadtbahn characteristics)

          • Nilo

            Except of course it doesn’t go from Grade separated in the center to not-grade separated outside of it, because the extension south of the Airport and across the Lake to Bellevue are both going to be grade separated.

          • fjod

            Intermittent grade separation on outer limbs is quite common on Stadtbahns though; Dortmund has a lot of it for example.

  7. Richard Gadsden

    Manchester (UK)’s tram system has reached the point that they are now proposing building a city-centre tunnel, which I think would qualify as a Stadtbahn by your definitions.

    The proposal documents are here: https://www.manchester.gov.uk/downloads/download/7277/draft_city_centre_transport_strategy_2020 but I can save you some time by quoting the entire two sentences that cover it:

    “We will look at the feasibility of further capacity expansions of the network through a Metrolink tunnel under the city centre. This solution would avoid taking scarce street-level space to expand the network and to facilitate longer vehicles.” Metrolink is the name of Manchester’s tram network.

    The timetable suggests completion for 2035-2040, which would explain the lack of detail.

  8. Max Wyss

    Stadtbahn does not necessarily mean that tunnels are involved.

    My first contact with Stadtbahn was in München after the network reduction caused by the U-Bahn. The remaining tram lines were then rebranded as “Stadtbahn”. Those lines did have, however, a considerable amount of grade separation.

    That said, the border between “Tramway”, “TramTrain”, and “Stadtbahn” are not very strict.

    Another example is the “Stadtbahn Glatttal” in Zürich (that’s the original name), which actually does have a short tunnel, but this more for topography reasons. Nowadays, the “Stadtbahn” has been skipped, and the network (well, line) is called Glatttalbahn. Its feature is that pretty much everything is grade separated, mainly on ground level, but there are two viaducts, one of them a good kilometer long, containing a stop; the other one actually also contains a stop.

    A few hundred kilometers towards the North, we have Bruxelles. They have several underground tramway lines, but those are/were called “pre-Metro”.

    • Alon Levy

      My understanding is that some German cities call their streetcar systems Stadtbahn because it sounds better, same way some regional systems with a train every hour on each branch call themselves S-Bahn.

      • Herbert

        Technically speaking, Karlsruhe may “earn” its “Stadtbahn” name as they are building a downtown tunnel under the name “Kombilösung”

    • JulianD

      With regards to Zurich:
      I think especially the city centre would be in need of a Stadtbahn system (with tunnels) considering the congestion and as a result the speeds that are reached there. But as we all know it won’t happen before like 2035 or so.

      • Max Wyss

        In fact, in 1962, the voters of the City of Zürich refused such a project, which meant to put most of the lines in the center underground. At that time, of course, to make space for more cars…

        Nowadays, with a few exceptions, most of the lines are soft grade separated in the center, or in pedestrian zones. (Soft grade separated means that there are no physical barriers, but markers. Signal priority helps clearing the space in front of a tram.

        That said, it is not likely at all for Zürich to go more underground. Also note that particularly in the area around Hauptbahnhof, there are already quite a few tunnels, meaning that an underground tram had to be really deep underground. Not worth it…

        • brendan dawe

          I’ve never heard of ‘soft grade separation’. But if I’m reading correctly, you’re describing rights of way that are..at grade?

          • Eric2

            So not grade separated.

            In my transit class in university we discussed 3 types of ROW:
            Type C – mixed traffic with cars
            Type B – separate lanes, at-grade intersections
            Type A – grade separate

            I’m pretty sure what Zurich has is Type B. No grade separation, either from cars or from crossing tram lines. Thus a need to wait for both at traffic lights.

        • threestationsquare

          Having dedicated lanes is better than nothing but the trams in central Zurich still have to wait at stoplights for cross streets. The ones in pedestrian areas also have to go slowly for the safety of pedestrians who might cross in front of them. It’s not really reasonable to compare this to grade separation.

          • Max Wyss

            If I remember correctly, the Bahnhofstrasse between Paradeplatz and Hauptbahnhof has a speed limit of 36 km/h (if I don’t forget it, I will check next time I go to Zürich). People are actually quite aware of the tram lanes and don’t get in the way…

  9. AJ

    As df1982 says, Seattle already sorta does this with a downtown tunnel and then surface running in SE Seattle and under-construction in Bellevue & Redmond. Both surface running segments will be branches of the core subway through downtown.

    A future line (Kirkland to Issaquah) is fully funded yet vaguely designed, but the current alignment interlines with East Link in Bellevue, sharing 3 stations and Bellevue’s short tunnel, before branching out to Kirkland and Issaquah. The Kirkland alignment is at grade, so particularly with further extension it will look more like a stadtbahn branch?

    The ‘ST2’ segments under construction now are not stadtbahn, but after Sound Transit is builds a 2nd tunnel through downtown for more trunk service and extends light rail further and further afield, there should be good opportunities for branching and surface running in some of the secondary cities. Stadtbahn should be a great template for future investments beyond those currently funded, both within Seattle and throughout Seattle’s region.

    • RossB

      It is a judgement call, but if you consider Portland to be “Fast in outlying areas”, then I think you would say the same thing about Seattle’s system, now, or in the future. It isn’t so much whether it runs on the surface, but how fast it runs there and how the rest of the line works. In Seattle, the line runs on the surface while, then goes underground, then above ground, etc., keep very good average speed.

      My guess is that there are more examples of this sort of thing with buses (i. e. open BRT, with a tunnel downtown) and Seattle was one of them. While many of the buses ran on the freeway, others ran on the surface, and took their time to arrive at the downtown bus tunnel.

  10. Martin

    San Francisco Muni is probably best example where surface lines were put into a tunnel.

    St Louis Metrolink also has a tunnel section in downtown using old freight tunnel.

    • Alon Levy

      Yeah, Muni Metro is the third main US example and the only recent one, together with the Green Line in Boston and the Subway-Surface Lines in Philadelphia.

  11. Thomas

    The most obvious stadtbahn possibility in Ottawa is connecting the proposed Gatineau LRT to the Confederation line tunnel. If it crosses using the Chaudiere bridge it could connect to the Confederation line just as it enters the tunnel west of downtown. Unfortunately that level of cross-border transit integration doesn’t seem to be treated as an option and there’s been talk of a second tunnel right beside the existing one. Just recently there’s been news coverage of transit advocates proposing a surface-running loop connecting both downtown cores (https://www.transitloop.ca/).

    The other seeming possibility is connecting street-running rail on Rideau St./Montreal Road to the tunnel, but I imagine it would be too expensive to join the tunnel where it’s still very deep. It could easily join up with the loop if it gets built though. Other than these, a surface line branching off the eastern side of the Confederation line (which currently has no planned branches, unlike the western side, which has one under construction and another that’s often discussed) would make sense. Either south along Main Street, south into Alta Vista or north into Vanier if nothing gets built on Montreal Road.

  12. Nathan Landau

    The interesting thing about Muni Metro in San Francisco is that the outer, streetcar lines were built in the early 20th Century, with one recent exception. The Downtown tunnel was built in the 1970’s, in space left available in the BART tunnel.

  13. Lee Ratner

    The closest to a Stadtbahn system in the United States is the light rail portion of the San Francisco light rail system. The lines run down a shared tunnel in part and the basic system was designed to take residents to and from downtown. In an ideal universe, the Key System would have been turned into a light rail system for the Oakland-Berkeley area rather than dismantled.

  14. Josh

    What about Los Angeles? There is a central downtown tunnel being built to connect branching light rail lines, which are mostly at-grade.

    • threestationsquare

      The branches are not mostly street-running or street-median-running, they’re mostly on legacy rail rights of way with some grade-separation and crossing gates. So right now it’s tram-train, and when the downtown LA tunnel is completed it will arguably be “light-metro-with-some-gaps”, though since the street-running will still be mostly in denser sections (downtown Long Beach, downtown Santa Monica) with grade-separation and private right of way mostly in less dense sections (Arcadia, Compton, Palms) I’d say it will still be closer to tram-train than subway-surface/stadtbahn.

  15. BindingExport

    where did u get the “so few people work in the center” for Addis. Merkato alone has 7,000 business attracting 100,000s of costumers each day. It’s the single most important destination for people in Addis.

      • BindingExport

        Well public transit services (Anbessa+LRT) in Addis have a combined daily ridership of almost a million. On top of that there’s privately operated transit (minibus taxis) accounting for 40% of overall transit ridership. The city also has built 100,000s of condominium units on the outskirts of the city with people who were resettled from the city center depending on Anbessa and the LRT to access their income opportunities.

          • Eric2

            Why is that relevant to the question of whether jobs are located in the center?

        • threestationsquare

          In that light it seems a bit odd that Merkato is on a branch of the Addis light rail rather than the trunk? There’s even an at-grade road crossing right next to it. Is there a major destination at Tor Hailoch that led them to decide to send half the trains there rather than to Merkato/Piazza?

          • Eric2

            In the longer term they should make their system into a triangle.

            One east-west line already existing
            One north-south line incorporating the current south branch, plus an extension north
            One southwest-northeast line incorporating the bend around Merkato

            All should be grade separated for higher frequency (they honestly are not far from that on the existing segments)

  16. threestationsquare

    Anglosphere light rail systems, categorized:

    Priority right-of-way in the core, priority right-of-way outside (“light metro” or just “light rail” if there are still a few gaps): Boston D, Charlotte Blue, Denver C/E/W, Edmonton, Los Angeles (especially after the Regional Connector opens), Ottawa, Pittsburgh, Saint Louis, San Diego Green, Seattle

    Street right-of-way in the core, priority right-of-way outside (“tram-train”): Adelaide Glenelg, Baltimore, Buffalo, Birmingham, Calgary, Croydon, Dallas, Denver D/F/H/R, Dublin, Edinburgh, Jersey City HBLR, Manchester Altrincham/Bury/Didsbury/Rochdale, Melbourne 96/109, Minneapolis Blue, Norfolk, Nottingham, Portland MAX, Sacramento Blue/Gold, Salt Lake City, San Diego Blue/Orange, San Jose, Sheffield Yellow, Sydney L1, Waterloo-Kitchener

    Priority right-of-way in the core, street right-of-way outside (“subway-surface” or “U-stadtbahn” or just “stadtbahn”): Boston B/C/E, Cleveland Blue/Green, Philadelphia 10/11/13/34/36, San Francisco J/K/L/M/N

    Street right-of-way in the core, street-right-of-way outside (“tramway”): Adelaide Botanic, Canberra, Charlotte Gold, Denver L, Houston, Melbourne other than 96/109, Minneapolis Green, Newcastle (Australia), New Orleans, Philadelphia 15, Phoenix, Sacramento Green, San Francisco E/F, Sydney L2/L3, Tacoma, Toronto, Tucson, and anything called “streetcar”

    Debatable: Boston Mattapan, Gold Coast (Australia), Manchester Airport/Ashton/Eccles/Trafford, Newark, Philadelphia 101/102, Sheffield Blue/Purple

  17. Henry

    Would Stadtbahn be a good fit for circumferential lines?

    The example that I can think of that would most likely fit would be Flushing in Queens, where multiple very frequent bus routes converge onto a rather small, congested two-lane Kissena Blvd (before it merges onto the bus sewer that is Main St). And the outer boroughs of New York have a fair amount of these small corridors where lots of buses converge for at least a bit (181 St in Manhattan, Fordham Road in the Bronx, all of the Flushing-Jamaica bus lines, Brooklyn College, etc.) where even in a world where subway extensions were affordable, you wouldn’t branch to serve all of those routes.

  18. Herbert

    Nuremberg should’ve built a Stadtbahn instead of that godless abomination they have now… But now Nuremberg city politics are so effed up, they can’t even build a tram through the northern old town which has a benefit cost quotient of like 5….

    • threestationsquare

      I think I’ve seen the tram tunnels opened in 1938 in Nuremberg’s Bayernstrasse area (built so that Nazi rallies wouldn’t disrupt the tram network, as I understand it) characterized somewhat dubiously as Germany’s first U-Stadtbahn. (Though I think the title rightly belongs to Cologne’s tunnel opened 1968.)

  19. Pingback: Tram-Trains | Pedestrian Observations
  20. Pingback: The German Way of Building Rapid Transit | Pedestrian Observations

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