Federal Way Link has broken ground, extending Seattle's existing light rail line three stops further south.

https://www.soundtransit.org/system-...n/news-updates

This flyover is pretty good. https://youtu.be/dHH5Nthscek

Edit:

Also the Redmond extension is underway, extending beyond the East Link the year after it opens. https://www.soundtransit.org/system-...n/news-updates

And the Lynnwood extension is underway, extending beyond Northgate a couple years after that opens. https://www.soundtransit.org/system-...n/news-updates

^Good stuff.

Though I have always felt that American light rail projects tends to over rely on aerial structures where trench cuts and underpasses would be much more aesthetically pleasing and long-term sustainable. This is often the practice in Europe with stronger land use standards and a finer tuned cultural investment in low-impact design but often American projects that are at the whim of a political term often are engineered by the lowest common denominator, even if that means it's ugly and/or you're tearing it down and rebuilding it in 50 years.

Have any modern light rail projects in the USA been torn down and rebuilt in the last 50 years? 60 years? 70 years? Vehicles have been replaced, but have any elevated light rail structures been replaced?

Well there aren't any light rail aerial structures that old yet. I don't have much doubt though that many recent light rail aerials and grade separation flyovers made of concrete probably will have to be rebuilt after they reach 50 years old.

Maybe they will, maybe they will not. Like you say, it is too early to know.
Never-the-less, with transit tracks within cuts, roads and other things are built over them - and guess what do you think most are constructed with, the same concrete used by transit systems.
So either way, 50 years afterwards will determine which is better, replacing light rail flyovers or street flyovers, assuming all will need to be replaced.

It's a lot easier to replace a roadway bridge over an open cut than it is to shut down a rail line to replace its own r.o.w. bridge over a roadway.

Light rail in Seattle is generally more difficult than the Federal Way extension. Usually it involves creating new ROW vs. the easy freeway margin. Tunnels, bridges, and steep slopes are common. Building in dense neighborhoods is common. Two stretches of the current line have street crossings, which is also a capacity and speed issue. I shudder to think about retrofits or rebuildings in 50 years or whenever. That would probably involve all-new ROW because the existing lines are already in tight places.

We have a long history of public works needing to be replaced or heavily retrofitted. The West Seattle Bridge (freeway) is in a two-year closure due to potential failure, and that's if it can be retrofitted. We've recently replaced the 520 floating bridge because the old one was at the end of its lifespan. We recently replaced SR99 through Downtown with a new deep tunnel mostly because the waterfront viaduct was a seismic risk. The Magnolia Bridge was temporarily closed and seismically upgraded after a landslide weakened it, and it'll need to be replaced. The Kingdome had a roof tile issue that required temporary closure and massive work.

We've also had disasters not averted. One of the I-90 floating bridges on Lake Washington sank during another refurbishment (air tanks left open during a holiday weekend). The Hood Canal floating bridge failed in a storm with people on it. The Tacoma Narrows suspension bridge failed in a storm with people on it.

That said, the design and construction professions know more today than they used to. Forces and time can be modeled far more accurately. Sometimes that means reducing material use and using new designs (potentially introducing new risks), but I suspect that even then the result will be longer lifespans, particularly for public work that's designed to high lifespan standards.

In Boston, the green line is being extended, which requires shifting a portion of track. As part of that work, they are removing more of the elevated viaduct than needed to build it new. They are also using the time to repair the rest of the viaduct.

The Green Line is a light rail system run by the Massachusetts Bay Transportation Authority (MBTA) in the Boston, Massachusetts, metropolitan area. It is the oldest Boston rapid transit line, and with tunnel sections dating from 1897, the oldest in America. It runs as a deep-level subway through downtown Boston, and on the surface into inner suburbs via four branches on several radial boulevards. It crosses the Charles River on the Lechmere Viaduct built in 1912, over 100 years ago. It's other major elevated section is the Highland Branch of the D branch, a former commuter rail line.

The first section of what became the Highland branch was built by the Boston and Worcester Railroad between Boston and Brookline in 1848. The Charles River Branch Railroad, a forerunner of the New York and New England Railroad, extended the line to Newton Upper Falls in 1852. The B&A bought the line in 1883 and extended to Riverside, rejoining its main line there. The line was closed in 1958 and sold to the Metropolitan Transit Authority (MTA), which reopened it in 1959 as a light rail line. 1883 is almost 140 years ago, and 1959 is just over 60 years ago.

MBTA is just now rebuilding bridges and viaducts built over 100 years ago. That's significantly longer than 50 years.

The Boston Green Line has zero to do with the kind of recent LRT infrastructure I am referring to....come on man. I'm talking about the dozens of concrete overpasses you see on the "rollercoasters" like LA Expo Line, Charlotte Blue Line, and the aerial structures like these in Seattle.

Thanks. I added the Seattle extensions. For now all the Seattle projects are listed combined as a single bullet point. If someone would care to work out exactly how to list each individually, I'd be happy to edit.

The Phoenix Northwest Phase 2 light rail extension is now under construction.

https://www.valleymetro.org/project/...e-ii-extension

The N Line in Denver has opened today:
https://www.rtd-denver.com/fastracks/n-line

This is likely the last new rail line opening in the US in 2020. It is possible (but seems unlikely) that Canada's GO Transit extension on the Richmond Hill line to Bloomington Rd will open. Metrolinx hasn't provided an update on the project in a while.

Phoenix added and Denver moved to complete.

2020 will be by-far the least active year in terms of openings since I began compiling this list in 2012.

Here's what I have found for 2021 rail openings in US/Canada. A number of these projects have been postponed into 2021, so it will be nice to see them finally open.

• Charlotte CATS Gold Line Phase 2 - Jan 2021 - https://www.wfae.org/post/streetcar-...elays#stream/0
• Honolulu HART Phase 1 - Mar 2021 - https://www.staradvertiser.com/2020/...back-to-march/
• Washington WMATA Silver Line Phase 2 - July 2021 - https://ggwash.org/view/78978/metro-...-opens-service
• Seattle Sound Transit Northgate Line - Sept 2021 - https://www.soundtransit.org/system-...ink-light-rail
• Boston MBTA Green Line Extension - Dec 2021 - https://www.wbur.org/news/2020/01/28...k-mbta-closure
• Edmonton ETS Valley Line Phase 1 - late 2021 - https://edmontonsun.com/opinion/colu...ine-lrt-delays
• Los Angeles Metro Crenshaw/LAX Line - late 2021 - https://la.streetsblog.org/2020/04/0...ix-months-ago/
• San Diego MTS Blue Line Mid-Coast Extension - late 2021 - https://www.nbcsandiego.com/news/loc...demic/2314570/
• Philadelphia SEPTA Regional Rail Wawa Extension - end 2021 - https://iseptaphilly.com/blog/elwyntowawa
• San Francisco Muni Metro Central Subway - end 2021 - https://www.sfchronicle.com/business...n-15562807.php
• Phoenix Valley Metro Tempe Streetcar - 2021 - https://www.valleymetro.org/project/tempe-streetcar
• Montreal REM Phase 1 - 2021 - https://rem.info/sites/default/files...N_20191024.pdf
• Toronto GO Transit Richmond Hill line Bloomington Rd Extension - likely to open in 2021 if not opened in 2020 (no recent updates) - http://www.metrolinx.com/en/greaterr...ington-go.aspx

Cirrus, I also noticed that the SMART Larkspur extension is listed in the first page run-down. That project opened in December 2019. They do have a new extension underway, north to Windsor. It's about 3 miles in length.
http://sonomamarintrain.org/construction-updates

Edited to reflect SMART. Thanks!

I don't think what you're advocating is very easy. If you cut through a major street instead of going over it, where do you put the sewer lines? Water lines? Electrical and phone lines? Realistically the only options are to either go over utilities or go under them, which would mean a tunnel, not a cut.

Construction has begun in Northern Indiana on a new branch to the South Shore train.

https://abc7chicago.com/travel/south...y-ind/7449680/

I drove by the new GO station in Toronto for the Richmond Hill line on Saturday and it looked almost complete. If it doesn't open by the end of this year it will be early 2021.

Orange County streetcar
 

We took this trip to Garden Grove
It smelled like Lou-dog inside the streetcar, oh yeah...

The first section of track has been inserted for the Orange County streetcar.

https://pbs.twimg.com/media/EpUsE1DU...jpg&name=small

https://pbs.twimg.com/media/EpUsFjHU...jpg&name=small

Photos courtesy of City of Santa Ana's Twitter feed.