The previous post opined Sound Transit Board's "unbridled" realignment ignored the end of ST3 taxes in 2041. That it failed to provide the "project scope discipline" needed to limit funding to what voters approved with ST3 passage in 2016. This post proposes delaying realignment until Northgate Link operation demonstrates their "Baseline" extensions' benefits. That any realignment should also be paid for by 2041 when ST3 taxes end.
Any realignment should recognize the limits from routing the "Baseline" extensions through the Downtown Seattle Transit Tunnel (DSTT). A 2004 PSRC Technical Workbook, "High Capacity Transit Corridor Assessment", funded by Sound Transit, concluded the DSTT stations limited trains to 4 cars. That safe operation required a minimum of 4 minutes between trains.
They assumed each car could accommodate 148 riders, limiting capacity to 8880 riders per hour in each direction. While Sound Transit ridership projects presume more "optimistic" capacity, none of the "Baseline" extensions will increase DSTT capacity. Thus riders added will reduce access for current Central Link riders.
The Northgate Link debut this fall will demonstrate DSTT limit on "Baseline" extension ridership into Seattle. Whether Sound Transit's website was justified with claims for 41,000 to 49,000 daily riders by 2022. Will routing "Baseline" extension through DSTT limit current Central Link riders during peak commute?
None of the "Baseline" extensions include the added parking needed to increase access to light rail at their stations. Instead Sound Transit is choosing to use the extensions to replace bus routes into Seattle. Thus, "Baseline" operation will reduce total transit capacity into the city. The Northgate Link debut will demonstrate whether replacing bus routes into Seattle reduces congestion into the city.
The debut will also demonstrate the high cost of operating "Baseline" extension trains. In their 2021 budget, Sound Transit assesses light-rail operating costs as $30.17 per mile per car. Extending the route the 4.3 miles from UW station to Northgate and back adds $260 to the operating cost for a light rail car. Sound Transit current operates 3-car trains, so extending the route to Northgate will add $780 to a round trip.
Sound Transit earlier scheduled Northgate operation to include 6 hours of peak-operation 8-minute intervals, 10 hours of off-peak 10-minute intervals, and 2 hours of late-night 15-minute intervals. That schedule requires 113 round trip routes each weekday so Northgate operation will add $88,000 to daily operating cost for 3-car trains. (When East Link begins operation Sound Transit will be forced to use 4-car trains to make up for having only half the DSTT trains. The additional car adds another $29,300 to daily costs)
The added cost along with number of riders added at the three Northgate Link stations will establish a cost per boarding for the extension. Their fare box revenue can be subtracted from boarding cost to determine subsidies needed to cover funding shortfall.
The results will also "inform" likely results with other "Baseline" extensions. Northgate Link ridership can be compared to Sound Transit's website projections for 41,000-49,000 daily riders by 2022. Whether transit riders are willing to endure the hassle of transferring to and from light rail for their commute into and out of Seattle.
The Northgate debut clearly "informs" on the Lynnwood extension operation. Sound Transit's website projects the extension will add 47,000 --55,000 riders by 2026. Yet they don't add significant parking at any of the extension's 4 stations. Again using the extension to replace bus routes to provide riders into Seattle.
Yet Sound Transit already intends to force those willing to transfer to light rail to transfer at Northgate. Rather than adding transit ridership, the extension simply replaces bus routes from Lynnwood to Northgate. Without added access to stations the Lynnwood Link will do nothing to increase transit ridership intoSeattle.
Using light rail to replace the 8.5-mile bus routes from Lynnwood to Northgate adds 17 miles to round trip. The $30.13 cost per mile adds $512 per car per trip; $57,900 per car per day for 113 trips; $174,000 for 3-car and $231,000 per day for 4-car trains. Again, without added access, to replace bus routes between Lynnwood and Northgate.
Unfortunately it's doubtful anything can be done about the $1.7B Sound Transit will spend completing the extension. However they could mitigate the operating costs by terminating some light rail trains at UW Station. Use buses for the commute from Seattle to Northgate and Lynnwood after 7:00 pm. Sound Transit budgets buses at $12.95 per mile. The 16 miles to Lynnwood and back would cost $414, a fraction of the $3100 for a 4-car train the 12.8 miles from UW to and from Lynnwood.
(While not a current "Baseline" extension, Northgate operation should end any attempt to extend light rail to Everett. Spending untold billions for the 16.3-mile extension would add $982 per car to round trip costs. Again, without additional access, primarily to replace bus routes to Lynnwood costing a fraction of light rail to operate.)
The Northgate Link debut will also "inform" Sound Transit's East Link. Whatever capacity it demonstrates will be halved for the route to Bellevue. While nothing can be done to increase that capacity, the results could be used to mitigate the damage by ending Sound Transit's "bus intercept" agreement to terminate I-90 bus routes on Mercer Island. Allowing buses to continue into Seattle would add needed transit capacity into the city.
The Northgate debut will also "inform" the "Baseline"extension to Federal Way. Whatever capacity it demonstrates will be halved when East Link begins operation in 2023. How much does its capacity exceed projected needed Central Link capacity from Angel Lake into Seattle? Does that available capacity justify Sound Transit spending $1.3B needed to finish the extension? Especially since the 5.3-mile route adds $1280 to each 4-car round trip
The Northgate debut demonstration of the Sound Transit light rail spine's limited capacity could prompt expediting light rail extensions from West Seattle and Ballard. The two routes are far shorter than those to Lynnwood and Federal Way, reducing operating costs. Neither displaces current light rail riders. Sound Transit estimates total daily ridership at 79,000 to 94,000. Both would benefit from the 5 stations on each extension having 70-80% of riders within walking distance, far greater than the 25-35% for Federal Way, minimizing the need for additional parking.
The bottom line is the Northgate Link debut will "inform" whether Sound Transit should have extended light rail across I-90 Bridge or beyond UW Stadium station to Northgate. Does the DST have the capacity needed to reduce congestion into Seattle? Will half that capacity make up for the confiscation of I-90 Bridge center roadway.
Will replacing bus routes with light rail trains reduce I-5 or !-90 congestion? Will light rail spine operating costs dwarf fare box revenue? Should realignment expedite West Seattle and Ballard extensions not delay them?
Sound Transit should delay any realignment until Northgate Link operation answers those questions. Any realignment should result in extensions paid for in 2041 when ST3 taxes end. Ending extensions beyond Lynnwood and diverting Federal Way funds to West Seattle and Ballard extensions would do so.