Pulling together some suggestions from the comments of the series prologue, part 1, part 2, part 3, and part 4…

Vancouver: Alon Levy reminds us to look at Skytrain’s viaducts in Greater Vancouver. Skytrain represents the kind of future for rapid transit this series means to investigate, baked right into the system’s name: expansion of transit aboveground, rather than under.

Skytrain’s fully automated, fully grade-separated network includes underground transit in dense areas and along narrow streets, but makes extensive use of elevated rail along wide streets and freight rail rights of way (active and dormant). Jarrett Walker discusses the virtues of the Skytrain system, above and beyond that of regular rapid transit – with the automated trains allowing for increased frequencies without increasing the associated operating costs:

Light rail is wonderfully flexible, able to run onstreet with signalized intersections, and across pedestrian zones, as well as in conventional elevated or underground  profiles.  Driverless metro must be totally grade-separated, which in practice usually means elevated or underground.  SkyTrain got its name because the original lines were mostly elevated, though the newest, the Canada Line, has a long underground segment.

The system’s most recent addition, the Canada line, features elevated sections for the two southern branches – one that goes to the airport, and one to redevelopment areas in Richmond.

By placing the line alongside the roadway when next to surface parking, they’ve managed to expand the sidewalk without imposing too much on the pedestrian environment. The benches and trellises around the columns are a nice touch. The single guideway for both tracks helps minimize the bulk of the guideway. When those parking lots are redeveloped, they can front on the sidewalk without overshadowing it.

Older elevated guideways in the system include center running sections through suburban land uses:

Some sections run along alleyways.

Other sections combine separate and adjacent right of way with berms and greenery:

Vancouver provides lessons for rapid transit expansion in that it uses elevated rail through suburban-style rights of way.

Tysons Corner:

The Silver Line extension of Washington’s Metro system to Tysons Corner follows some of same principles as Skytrain, but without the same quality of execution. Part of the challenge is the landscape (Tysons features some wider roads than Richmond), and part is in the transit infrastructure.

Tysons tunnel proponents claimed that a Spanish-style large-bore TBM could tunnel through Tysons at lower cost than elevated rail. The authorities rejected this argument after some study, and with good reason. It may be true that the Spanish can build transit tunnels extremely cheaply (they can!), but it makes little sense to compare American elevated costs with Spanish tunneling costs.

Instead, it’s illustrative to look at relative costs of construction types. If the contractors could’ve built tunnels at the same cost as the Spaniards, they could’ve built elevated rail for less money, as well.

Along Route 7, they’re starting to install sidewalks, but the pedestrian environment is still lacking.

There are opportunities for infill development along these new sidewalks, but sidewalks adjacent to a high-speed stroads isn’t the most compelling environment. Other new transit-oriented development in Tysons isn’t attempting to turn the existing main stroads (routes 7 and 123) into nice streets, but rather add a pedestrian layer on top of the current auto-centric network.

Table of contents:

• Prologue
• Part 1
• Part 2
• Part 3
• Part 4
• Part 5