Sound Transit’s Real Complexity Problem

The March 7^th Seattle Times Traffic Lab article “Report: Light rail too complex for its own good” details “operating problems associated with power problems, weak governance, inefficient use of maintenance crews, and a lack of crossover rail switches to avoid blockage”.  The problem apparently is due to the sensitivity of Sound Transit’s “Rail-to-Ground” selection for power system .  Proposed recommendations would allow trains to bypass problems and maintain Sound Transit’s promised four-minute-intervals in 2026.

This post opines the “Complexity” resulting from Sound Transit’s decision to route Line 2 trains through DSTT to Lynnwood and beyond dwarfs the power system problem.  Sound Transit currently routes Line 1 trains every 8 minutes between Angle Lake and Lynnwood. They could have “maintained the frequency of trains every four minutes that’s promised in 2026” by doubling the number of Line 1 trains. 

Instead, Sound Transit chose to provide additional trains to Lynnwood by routing Line 2 from Redmond via International District/CID station through DSTT and maintain current 8-minute intervals to Angle Lake and presumably to Federal Way when it debuts in 2026.

 The problem becomes how do they assure that Line 2 routes from Redmond arrive at International District/CID both 4 minutes before and after Line 1 routes from Angel Lake and later Federal Way?  Line 1 schedules show 36 minutes from International District/CID to and from Angle Lake.  The extension to Federal Way will add unknown minutes in both directions.

The current Line 2 schedule shows 17 minutes from Redmond Technology Center to South Bellevue T/C.  The extensions to Downtown Redmond and across I-90 bridge will add unknown time to the Line 2 route from International District/CID to and from Downtown Redmond.  Assuring the Line 1 and Line 2 trains arrive at the International District/CID 4 minutes apart constitutes a real Complexity problem.

It all could have been avoided if Sound Transit had simply doubled the Line 1 trains and terminated Line 2 at International District/CID.  Line 1 riders from South Seattle would’ve benefitted from additional capacity and Line 2 riders from service that matched east side demand.