Friday, September 19, 2025

Problems with 2 Line's "Engineering Success"

 A recent Seattle Times Traffic Lab article, “Seattle light rail makes history with test run across I-90 bridge” detailed Sound Transit running an electric powered railcar across the bridge at up to 55 mph. The results validated the Sound Transit project manager’s confidence the trains can go full speed. The testing will continue until 2026 spring to confirm:

Four car trains, labeled as the 2 Line will travel all the way from Redmond to Lynnwood, sharing track in North Seattle with the older 1 Line

Yet there’s little evidence this "engineering success" will reduce congestion. The problem is 4-car light rail trains lack the capacity to attract the riders needed to reduce peak hour congestion on multi-lane roadways and cost too much to operate during off-peak.   

Sound Transit should have never been allowed to use the I-90 center roadway for light rail.  Doing so precluded two-way BRT with 10 times light rail capacity, 10 years sooner, at 1/10th the cost. The Washington Department of Ecology has raised concerns the stormwater from the tracks could pollute Lake Washington.

Sound Transit compounded the capacity problem by using light rail to replace bus routes across the bridge and routing the trains through DSTT to UW and beyond. They initially estimated 50,000 riders would use light rail.  The article’s claim for 10,000 Starter Line passengers presumably reflects the 9442 boardings in the July ridership report.  However, since each passenger presumably boarded to and from their destination only 4721 passengers used the Starter Line. 

It’s unclear how many Starter Line riders will be added by the extension and the 2 Line stops on Mercer Island and Judkins Park in Seattle. Sound Transit intends to add riders by using it to replace ST550 from downtown Bellevue into and out of Seattle.   The route’s June 4820 boardings presumably reflect 2410 passengers riding into and out of Seattle. Terminating ST550 limits Bellevue commuter’s access to transit to those within walking distance of T/C and East Main station. 

The need for I-90 corridor bus riders to transfer to and from light rail on Mercer Island for the commute will likely dissuade many commuters from using transit.  Again, it’s unlikely 2 Line operation will reduce I-90 corridor peak hour congestion.

However, its operation will add to the problems identified in the following from August 27th Sound Transit Board meeting:

Cost pressures related to improved service delivery could require approximately $5B more in year-of expenditure dollars

Routing 2 Line trains from Downtown Redmond Station (DRS) to and from the International District Station(IDS) will add 36 miles of revenue service.  At `$30 per mile  a 4-car train will cost $4320 per trip.  Sound Transit’s projected 2 Line schedule requires 122 trips, costing $527,040 daily.  

The Sound Transit decision to route the 2 Line through DSTT to Lynnwood also creates an operation problem.  It halves the number of 1 Line routes to SeaTac and beyond and complicates safely merging those routes when they return with 2 Line trains into IDS.  

Routing 4-car trains through Bellevue to Redmond will double the noise from Starter Line 2-car trains.  Sound Transit will presumably have to reduce 4-car train velocity along the route to avoid violating Bellevue noise limits.

The bottom line is the ability to route 4-car trains from Redmond to Lynnwood may be an “engineering success” but a transit system debacle. Sound Transit could mitigate the problem by terminating 2 Line trains at IDS. Let east side need define east side service,  Avoid the need to halve the number of 1 Line trains to Federal Way and set 1 Line service to meet Lynnwood need.

 

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