Sound Transit has recently reduced construction cost with smaller station designs (for example Alaska Junction) but their current four-car trains are 440ft long while Vancouver’s SkyTrains are only 280ft long. That still requires bigger, harder to locate, and more expensive stations. Due to automation SkyTrain can operate more frequently and therefore still handle higher ridership while providing higher convenience. Sound Transit has considered automation but is concerned about interoperability with current trains. They could add an operator on surface portions such as through Rainier Valley. If they would keep the Ballard line separate, then interoperability would not be an issue, but Sound Transit would need to worry about where to park them at night (“stabling”), clean them, and maintain them. When Sound Transit considered a starter line for Ballard, they concluded that they would need to build an operations and maintenance facility (OMF) in Interbay and that its cost would offset all savings. I gathered some ideas on how to potentially reduce such effort.
If you connect the Ballard (starter) line with the main line, you could still use the existing Central OMF in SODO. If such a connection is not feasible, then you could build a separate regular OMF or consider other options.
For maintenance, you could connect to the BNSF tracks at Interbay and SODO to move trains between the Ballard line and the SODO OMF during off-hours. As BNSF tracks are not electrified, you would need a separate locomotive to pull the trains. You could also truck the trains as these occasional maintenance events.
For nightly cleaning and monthly maintenance, you may still want a separate small cleaning center just like SeaTac airport cleans their people movers locally.
When Lynnwood Link opened, Sound Transit did not have enough stabling space at the Central OMF. They parked some trains at various stations at night. Operators had to pick them up there in the morning and park them there at night. Automated trains may operate through the night. If you do not want to operate through the night to maintain the tracks, you can park automated trains anywhere. They can wake themselves up in the morning, go through safety checks, and move to the first station by themselves. In fact, if Sound Transit wants to reduce service in the evening and start cleaning cars, they could send them to the OMF for daily cleaning and afterwards park them at any pocket track. If they want to reduce service further, they even reduce service to a single track towards the end of the line and use the other track for stabling.
This would reduce the size and cost of the OMF considerably. As automated trains can move (“shunting”) themselves in and out of the OMF, there is no need for shunting staff.
Sound Transit could even allow construction of transit-oriented housing above such facility as the Hong Kong MTA has done for example.
If Ballard trains don’t need to use the Central OMF in SODO, Sound Transit may be able to reduce the size of the Everett OMF. This may shift some of the cost.
I would hope by reducing the cost of the maintenance facility, Sound Transit would consider an automated Ballard starter line and shorter stations. Due to its lower cost, it could connect Ballard sooner and also be more attractive to riders due to its higher frequency and longer service hours.
