First, why is TOD (here, the T is for transit, as usual) sometimes not TOD? Today many mass-transit lines follow major highways, which are the primary mode of access to the area. They do that because following these highways is the easiest way to get a bus within range of a large number of homes and destinations that have been built along and near the highway. A lot of these routes were established and grew into popular, important “trunk“ routes in response to travel demand generated by development that formed around the highways. Metro's E Line is sort of like this and the A Line even more, but even bigger and more expensive projects do this: Sound Transit's current network looks a lot like the freeway network, and with a few notable exceptions will continue to through ST2 and ST3. If a freeway interchange is built, and then an office park next to it, then the interchange is expanded to handle the additional traffic, then express bus service is started, then eventually a train station is built there, and then part of the office park is expanded, is that really TOD? Or is that just a nice-sounding buzzword, while the expansion will mostly continue to lean on the freeway interchange for access? This comes up a lot around here, with recent and future redevelopment in places like Northgate, Lynnwood, and Bellevue's Spring District (along with many others).
What about the ERC? It's a defunct freight railway; within Kirkland the rails have already been removed and a temporary gravel trail constructed. Within Renton and southern Bellevue the trail is sort of hemmed in by Lake Washington, I-405, and steep slopes; there really isn't much room for development of any kind near it south of downtown Bellevue. Around and north of downtown Bellevue it used to provide rail access to some fairly large industrial lots; some of these are still industrial while others have newer big-box stores and car dealerships on them. Continuing north it backs up to some office buildings and apartment or condo complexes before entering Kirkland, where it runs along a hillside surrounded by expensive view homes (whose residents reliably agitate and file lawsuits over any proposed change to the corridor). North of that is old industrial Kirkland, some of which has been recently been replaced with low-slung commercial buildings. North of there, the Totem Lake area, named for a small lake but dominated by a massive freeway interchange, home to a chronically struggling mall and the hopes of generations of Kirkland leaders that they could focus growth out there (growing their tax base without pissing off people in older parts of town) by redeveloping it. After escaping Totem Lake the industrial character resumes, broken up by hillsides and the wineries of Woodinville.
So since the corridor's industrial peak it has already seen some changes, with mostly retail and commercial buildings replacing rail-dependent industries. Building out the trail and focusing planning resources along it might accelerate this change, and probably add some homes to the mix. It's hard to see much happening south of downtown Bellevue (because of terrain and physical obstacles), or in Woodinville (I think everything that isn't a hillside there is a floodplain; maybe some of the beer-and-wine businesses will open up trail-facing entrances and try to compete with Red Hook). Some parts in Bellevue could be really exciting. Through much of Bellevue the rail corridor is a big physical barrier that's near other parallel barriers (especially 405 and 520), so the areas near it aren't very cohesive. A good trail conversion would add lots of ways across it, connecting homes and destinations on either side in ways that haven't been possible before. On the other hand, taming the connections to downtown Bellevue would take a lot more work. In Kirkland I'm less excited. I've heard people from the city of Kirkland talk about these ideas, and they seem pretty excited. They mostly seem interested in accelerating the ongoing land-use changes along the corridor, which is OK; good, even, if it results in daily needs like basic shopping and childcare available within walking distance of more people. But it's mostly on pretty small slivers of land... until you get up to Totem Lake, which is what I think it's really about. Kirkland wants yet another hook to get some developer to make Totem Lake happen, for real this time.
Now here's the problem with any “transit-” or “trail-oriented” development project in Totem-Lake. ST3's 405 BRT plan includes a station in Totem Lake. That's one little bus station, about the size of the freeway bus station that's already there today. The ERC trail is one 12-foot-wide strip passing through the southeast quadrant of the neighborhood. So there's some transit, and there's a trail. But they're not all that big, they're not all that close, and they're not really connected to eachother. I-405 is really big, and it's the Prime Meridian of Totem Lake. NE 124th Street is really big, and it's the Equator. And they sure are connected, with a very large interchange right in the dead center of the neighborhood. Whatever good there is in 405 BRT (which I'm skeptical of in general) and the ERC Trail (plenty of good things, especially in Bellevue), we shouldn't pretend that they'll really change the game in Totem Lake, which will continue to be dominated by roads and parking lots. So we shouldn't let Totem Lake redevelopment be greenwashed by them. There are parts of Kirkland where low-carbon redevelopment is possible today and Totem Lake just isn't one of them without major infrastructure work.