Many of you sent your concerns about the placement of the East Link turn-back track to Sound Transit, prompted by Brent’s recent analysis of the problem. ST sent this thorough reply out to all of you and to us:
On behalf of the Sound Transit Board, CEO, and our staff, I wanted to thank you very much for taking the time to share your thoughts regarding the International District Station’s (IDS) design as it relates to Sound Transit’s light rail system. We greatly appreciate and share your interest in seeing the light rail system as well-designed and well-used as possible.
As background on the issue overall, when the ST2 regional light rail system is fully built out it will be important to be able to efficiently take trains out of service and return to the main operations and maintenance facility (OMF) in the SODO district of Seattle, south of the International District Station (IDS) and the Downtown Seattle Transit Tunnel (DSTT). Although the agency is planning to build an additional satellite vehicle storage and maintenance facility, all heavy maintenance will continue to occur at the existing OMF. We expect each light rail vehicle to cycle through the existing facility once a week.
Given this, Sound Transit has spent almost a year analyzing options for the best placement of a “turnback track” to allow trains from the East Link line to be taken out of service and returned to the OMF. The Pioneer Square and University Street stations do not have room to maneuver a four-car train between the platforms (length of switches on one end and room for a four car train), which left Northgate, IDS and Convention Place stations as the best options in terms of operations, construction impacts and cost.
The IDS alternative is superior to the Convention Place and Northgate options in a number of ways such as construction costs, shorter-term construction impacts and long-term/permanent operations. It also minimizes the amount of travel through the DSTT by an empty train and avoids problems such as maneuvering non-working vehicles through an active line and stations while on their way to repair. That’s an important factor because trains will operate every four to five minutes in the DSTT when the ST2 system is fully built out, and any stops, delays, or traffic in this location could delay trains and affect reliability not just at those stations, but across the entire system and all lines that connect with the tunnel.
The idea of converting the existing IDS layout to a center-platform station has indeed been considered and investigated, but the extensive costs and serious disruption to existing services that would be required to reconfigure the station layout effectively took that option off the table several years ago. Essentially, the entire north and south station plaza would need to be rebuilt in order to create and provide the necessary access to and from a center platform (a center platform is required to have the same sort of stairs and elevators to the plaza as the side platforms in order to meet current fire/life/safety regulations). This would require closing the DSTT to all service for several months and would cost exponentially more than the current plans, which we simply do not have funds for.
Leaving IDS as a two-platform station still allows for very easy transfers with multiple escalators and elevators on both platforms, and a short and completely sheltered walk from one side of the plaza to the other. These types of transfers are quite common and work very successfully in larger systems with lines running in multiple directions.
Given all of this, we can appreciate that a center platform would be more convenient for travelers heading south from the east, but the benefits do not outweigh the significant costs, construction, and long-term operational reliability and impacts of such a change.
I do hope this help provide some explanation and context on this topic, and again, we greatly appreciate your input and engagement. Our boardmembers review all input received from citizens such as yourself and will continue to keep your comments in mind as decisions are made on the project. If I can help further in any way, please feel welcome to contact me any time.
Correspondence Management Coordinator
Brent may have a followup on this issue shortly.