A visual survey of selected elevated rail viaducts: part 2 – best practices of integrating viaducts into urban designs

Continued from the prologue and part 1… A look at legacy examples of older elevated construction precedents. Some examples drawn from this post and this thread on the archBoston forums.

Berlin: As a part of his writing about elevated rail, Jarrett Walker takes note of Berlin’s elevated rail, and the use of space beneath them:

But the Stadtbahn is something else.  Completed in 1882, it runs east-west right through the middle of the city, with all kinds of urban land uses right next to it.  It’s a major visual presence in many of Berlin’s iconic sites, from affluent Charlottenberg to the Frederichstrasse shopping core to the “downtown of East Berlin,” Alexanderplatz.  It even skirts Berlin’s great central park, the Tiergarten, and looks down into the zoo.  If you were proposing to build it today, virtually every urbanist I’ve ever met would instinctively hate the idea, and if the idea somehow got past them, the NIMBYs would devour it.

Yet much of it is beautiful. Most of the viaduct is built as a series of brick arches.  Each arch is large enough to contain rooms, and today many of these are retail space, most commonly restaurants.  These restaurants put their tables outside, sometimes facing a park but still, unavoidably, right next to the viaduct, and they’re very pleasant places to be.  A train clatters overhead every minute or two, but it’s not dramatically louder than the other sounds of urban life, so it’s a comfortable part of the urban experience, devoid of menace.  I could sit in such a place for hours.

Indeed, the  four-track Stadtbahn cuts through Berlin on its own right of way, not in adjacent to or in the median of another street. Many streets run tangent to the elevated railway for segments, but much of the city directly abuts the railway.

Berlin Stadtbahn aerial image from Bing Maps.

Berlin Stadtbahn aerial image from Bing Maps.

By cutting through the city on a separate level and without directly mirroring the street grid, the transit network adds another layer to the cityscape. The city, both old and new (and yet to be built), has grown around the elevated rail:

Berlin Stadtbahn aerial from Bing Maps.

Berlin Stadtbahn aerial from Bing Maps.

At the street, many of the viaduct’s archways have been turned over to retail uses, activating what would otherwise be a barrier of dead space:

View of the same viaduct from street level. Image from Google Streetview.

View of the same viaduct from street level. Image from Google Streetview.

Jarrett’s post features a number of other images from Berlin, showing the various types of spaces the Stadtbahn creates. He closes asking if we might learn from these legacy examples in building new transit infrastructure:

Europe has some really beautiful transit viaducts, including some in the dense centres of cities.  Most of them are a century old, so the city has partly grown around them.  But the effect is sometimes so successful that I wonder if we shouldn’t be looking more closely at them, asking why they work, and whether they still have something to teach us about how to build great transit infrastructure.

Paris: Metro Line 6:

Paris Metro Line 6. Image from Google Streetview.

Paris Metro Line 6. Image from Google Streetview.

Line 6 runs down the middle of several wide streets, providing enough room for bike and pedestrian pathways beneath the viaduct, while also leaving enough space alongside for trees and landscaping. The aesthetic elements of the rail infrastructure (stone piers, steel spans) echo the architecture of the city as a whole.

Paris also has examples of old, now un-used vaiducts re-purposed as part of a vibrant cityscape:

Paris 2

Viaduc des Arts, Paris. Image from Google Streetview.

Above the viaduct is now an elevated linear park.

New York: In the comments of Part 1, Charlie asked about New York’s High Line. I did not initially include it, but I do think it offers an intersting example. The High Line (or what remains of it), like Berlin’s Stadtbahn, does not run directly above many streets. Also, the city grew around the infrastructure – in the High Line’s case of delivering freight to adjacent factories, that direct interaction was the very point of building the line.

Aerial view of the High Line weaving between and through buildings. Image from Google Maps.

Aerial view of the High Line weaving between and through buildings. Image from Google Maps.

Southern end ot the High Line, running adjacent to Washington St. Image from Google Streetview.

Southern end ot the High Line, running adjacent to Washington St. Image from Google Streetview.

One particular example of elevated rail in New York both looks to the past (we don’t build ’em like we used to) but could also learn from the repurposing of the spaces created under viaducts for uses other than storage. The Queens Boulevard elevated rail line runs down the middle of a wide street, with large archways beneath the tracks – currently used for parking.

New York - Queens Blvd 1

Queens Boulevard elevated rail. Image from Google Streetview.

Consider that when the line was built, the surrounding area was completely undeveloped. The city (and the roadway) emerged around the rail line, rather than cutting the rail line through an existing urban evironment (I don’t know that any single image better conveys the links between transportation, land use, and development). Meshing transit expansion into low-density areas is not just about transportation, but about re-shaping the city. Under the right conditions, it can work well.

New York has other examples of repurposing space beneath viaducts. While not specifically a transit example, the re-use of space under the Queensboro Bridge approaches in Manhattan is an example of what’s possible with some of these rail viaducts:

Queensboro bridge approach, New York. Image from Google Streetview.

Queensboro bridge approach, New York. Image from Google Streetview.

Short of re-purposing the space beneath the tracks, the Queens Boulevard elevated rail allows for a perfectly acceptable kind of rail, without shadowing the streets or sidewalks below, making use of the street’s wide right of way. Alon Levy takes note:

But when there is an el about Queens Boulevard, everything works out: the street is broken into two narrower halves, with the el acting as a street wall and helping produce human scale; the el is also farther from the buildings and uses an arched concrete structure, both of which mitigate its impact.

Any other examples of older elevated infrastructure we can learn from?

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5 comments to A visual survey of selected elevated rail viaducts: part 2 – best practices of integrating viaducts into urban designs

  • charlie

    Fascinating survey, thanks.

    The “building right next to viaduct” and “not using the street grid” do produce some interesting results.

    For the first, the Whitehurst largely does that in Georgetown. Amazing, those luxury condos don’t get much traffic noise. There is room for one more building on the usused federal land.

    And yes, running the train in tysons through what is no parking lots would have helped.

    The trees/greenery in the high line and paris also help break everything up.

  • Alex Block

    Great point about greenery softening the visual impact of these structures. Those trees in Paris are fairly mature, but it’s not like they’re huge, 100-year-old elms.

    The WMATA examples yesterday along Suitland Parkway feature the same benefit from greenery, but without much surrounding urban context at all.

  • The Queens Boulevard and Berlin examples really seem like missed opportunities we could have had in Tysons: cheap infill retail using the bridge structure as a roof. It would reduce the barrier effect of the median, focus activity near the stations, and set an example of urban form.

    This was the solution nobody was looking for because we were so set on fighting out the tunnel-versus- overground plan and trying to keep the project afloat. I certainly was guilty of believing that no viaduct could be attractive, and kept arguing for a tunnel. I was looking at the types without considering design. It’s the same trap that NIMBYs do, wanting to minimize the impact by making a building smaller, rather than better. Damn. Looking outside of the box is why Jarrett Walker is so great.

    I would really take a look at Otto Wagner’s Wiener Stadtbahn. The infrastructure is pretty street-friendly. It’s also very well designed, particularly the bridge over the Wienzeile.

    I don’t know much about it, but the Shinkansen is built on viaducts, which I think are occupied in some locations.

  • Alex Block

    The idea of making it ‘better rather than smaller’ is a good one. I think part of the takeaway from the first part in this series that looked at all of the pre-cast concrete options is that if you wanted to make the Tysons elevated viaducts smaller, you could have done so. The Silver Line’s viaducts are about the bulkiest, clunkiest ones I’ve found.

    At the same time, Tysons is pursuing a policy of pedestrianizing the place, adding a grid of streets, trying to make it function in a more urban way. They haven’t connected the dots yet. And, it’s understandable why: dealing with the spaces beneath the viaducts is a low priority compared to getting the transit built in the first place, or getting the street grid planned and built.

    I’ll have to look more closely at the Shinkansen viaducts. I’ve been trying to do some image searches from China and their Metro-building spree, but the China/Google fracas means no streetview. The current state of civil engineering and the realities of construction costs means that I doubt we’ll be seeing Berlin-style stone arches, but that doesn’t mean there aren’t creative ways to re-purpose that space beneath.

    I would also suppose that the retail uses in Berlin (aside from station areas) were not planned as a part of the viaduct’s construction, but merely filled the void once it was there.

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