Even a new bridge would be very expensive on the order of a billion or two.

Actually, it’s not “simple engineering stuff”. Because of the curved rise onto the transit structure above Royal Brougham that East Link will use, there is no possibility to connect westbound East Link to southbound Central Link and vice-versa via a “wye” between Stadium and International District.

The may be the possibility of putting a “pocket track” at ID Station into which the occasional East Link trains could pull, reverse direction and travel south to the airport. And vice-versa of course. But it would probably play hell with the schedule.

An expensive way to accomplish the same thing would be to use the space devoted to the HOV slip ramps just west of Rainier Station to provide a flying junction and elevated connection to just south of Mt. Baker station. It’s my understanding that East Link will take the entire center roadway for transit (buses will continue to operate among the light rail trains, but no private vehicles), so the slip ramps won’t be needed to let private HOV access to the main lanes for interchange with I-5.

I’m not saying this is COST EFFECTIVE now, or even when East Link fires up, but I think the necessary space is available should eventual demand for East Side-Airport trips arise. There is no doubt that that train would be WAY up in the air. And the merger with Central Link on MLK would be pretty dicey.

It wouldn’t be simple engineering. But it is at least possible.

Nice Job moderating this list! You have a very good sense of what needs to be said to keep people on task. i am a bus driver and would like to chime in. I live in Columbia City and the south end rail line is really working great for me. My commute is 1/3 the time it used to be.

East Link needs to go over both bridges! The East Side, Bellevue, Redmond, and Issaquah are all interconnected to Seattle. In one light rail vote that failed research for a line from Ballard along the 44 route to UW and over 520 to Overlake was REALLY exciting to me. This line needs to exist as well as the Seallte, I-90, Bellevue, Eastgate, Issaquah, Issaquah Highlands line. Connecting it all would be the 560 bus route converting to rail and and continuing over the west seattle bridge on the seattle side and continuing North-South in the 405 corridor to Kirkland Redmond Bear Creek. BOTH Bridges!! When you are criticizing one bridge over the other, try to think not about how we use transit now, instead try to imagine how the cities will evolve with a transit system that has several inter-crossed well planned routes. Watch MLK over the next few years, drive down it tomorrow if you have not been down that road in a while. It is amazing to see the growth, but what is more exciting is what is to come now that the train is moving. That is what will be great imagine how the cities will change when the train is traveling over both brides to ballard to west seattle north south. that is the vision, Do not settle for one bride!

Look at the Eastgate and the Issaquah Highlands Park and Rides! This is well planned out transit! The route 212 is one of the best buses in the system. It gets to downtown from the Issaquah Highlands Park and Ride faster than a 7 from Rainier Beach but it needs the capacity of a Light Rail train to fully come to fruition. Keep the debate going it is really exciting!

Paul Margolis
Transit Operator
Local 587

Pity they aren’t designing it with two lanes in each direction plus a rail line in each direction. Well, here’s to delay in the SR 520 project; maybe delay will lead to a saner result.

Obviously any bottleneck is a natural for rail; it should run over both bridges in the long run.

One additional tidbit is that the original design for the I-90 bridge from the 1970s assumed BART style heavy rail would eventually be installed, since this was the kind of rail transit assumed to be in the region’s future at that time. And now it turns out that light rail cars and the catenary infrastructure for power are HEAVIER than the same equipment for heavy rail.

There is tremendous momentum for government agencies at all levels to follow through on the ST2 vote and build passenger rail tracks on I-90. However, the environmental review process has at least a year left to run before a final Record of Decision is issued.

I also get incredibly smug smirks from anyone living in or near Montlake that ‘we’ won’t have any light rail over the 520 bridge and that is a good thing in their view.

Maybe connecting up toward the north will happen….and over between the eastside stations.

Fine, all should not devolve into a downtown seattle.

But I really wish we would at least build for possibilities when we make these investments.

above: a representation of why I-90 is a better choice

The diagram starts with the premise that the line starts where the I90 alignment ends. Take the I90 alignment and flip it. What you end up with is Issaquah/Factoria up 148th Ave NE through Crossroads to Overlake then Bell-Red to Bellevue and final 520 picking up Kirkland. It would be much faster to the U district, about the same to downtown and faster to the airport.

Either alignment can work. The big risk with 520 is it ties into a mega roads project which is in disarray. The advantage could be that since this is all being built from scratch it would be the chance to do it right for a minimum of added cost. The proposal for a SOV tunnel under the Montlake Cut becomes a tie in to North Link. It’s unfortunate that’s not a political reality. Even more unfortunate is that what we’ll likely end up with is a highway project that’s the most expensive ever built per miles of vehicle lane and one that’s only marginally more effective than what we have today. I know the bridge needs to be replaced before it sinks but when all the concrete is pour the “improvement” is about four miles of HOV lanes which just pushes congestion out to I-5, 405 and the U district.

The only way I see that rail could cross the lake along the 520 corridor would be building a separate bridge. Maybe if it was just for rail it could get pushed through but the expense would be prohibitive, well over a billion in today’s dollars. Think what the impact would be on East Link if WSDOT told ST the fees for using the center roadway on I90 are going to have to cover half the cost of the new 520 bridge.

Even if they did have funding to build a rail only bridge there would be a whole host of other problems. The alignment would have to be along the current 520 bridge; the new one is being built 100′ to the north. So on the west end it would have to go directly into a tunnel making it even more expensive.

They’re replacing the bridge and redoing all of the interchanges on the west side. I think it is now or never for a rail ROW over 520. One idea at Montlake is a tunnel under The Cut. If that were designed to accommodate rail in the future, and by designed I mean added not traded for vehicle lanes then the option would still be on the table but there’s zero support for building the bridge this way. And I don’t think there’s any talk of making the Portage Bay portion even “rail ready”.

A better trend would be whatever gets people who live in Seattle and work in Redmond to just move to Redmond.

For the money you’d spend on a line that might get you 50,000 riders per day, you could build lines elsewhere getting you 400,000 riders per day. It’s just not worth it.

Sure, it would be costly, but by my rough, completely unscientific measurements, it would be a 6 mile trip, instead of an 11-12 mile trip. Let’s say a straight line from 5th and Pike downtown to Bellevue Way and NE 6th Street in Downtown Bellevue, instead of the two circuitous highway routing schemes now being debated.

In terms of capacity, at least, there’s another factor. Before we close the center roadway to traffic, we’re adding HOV lanes to each direction of the outer roadway – doing this project and closing the center lanes already results in a slight increase in total bridge capacity. The center roadway is bottlenecked by the ramps/lights at either end (which was painfully clear during the I-5 closures last year) – so we only see 1800-1900 vehicles per hour today, and that’s pretty much maxed out. The HOV lane additions will add more capacity than that in each direction (remember that the center roadway only goes one direction at a time).

Light rail offers an eventual capacity of 12,000 people per hour per direction. While our initial service will be less than half that, ridership takes time to build and service can easily be added as that ridership increases. Also note that the highest ridership route across I-90, the 550, would be replaced by East Link.

Here’s a neat graphic showing the comparison and mentioning the rather dramatic increase in capacity that East Link would add to the roadway:
http://www.soundtransit.org/Documents/pdf/st2/I-90Lanes_LtRail.pdf

To answer your question more directly: I believe the I-90 center roadway gets 20-25,000 users daily. With light rail, assuming $2/gallon fuel, we projected 45,000 riders per day in 2030. We’ll have much, much higher ridership with $4.39/gallon (today). Those numbers also don’t include transit oriented development – I don’t even know if they include some of the massive residential construction already going on in downtown Bellevue.

As the center roadway lanes are already essentially maxed out today, light rail offers actual ridership well over double the existing use, and eventual capacity an order of magnitude higher than the existing lanes.