At the Sound Transit Board’s executive committee today, ST CEO Peter Rogoff said that Sound Transit will be the sole operator in the Downtown Seattle Transit Tunnel (DSTT) starting March 23, 2019, as King County Metro vacates the tunnel.

Rogoff also announced that ST will run trains in both directions on a single track for a yet to be determined part of 2020, as part of East Link construction.

ST spokesperson Geoff Patrick said that six minute peak headways will remain the same after ST takes over the tunnel, but the trains will “actually be able to meet them.”

At present, bus-related impediments, like onboarding and payment, prevent ST from meeting ideal reliability standards in the tunnel. After the changeover, trains will be able to operate at higher speeds between stations, with less time spent idling between stations or lingering at the platform.

Patrick said that “there’s no way to finish construction” without the single-tracking, which will be located just south of the Chinatown/International District station. Switches will be installed in the tunnel guideway, to connect East Link’s ramp—which previously carried Eastside-bound buses into the DSTT—to the existing rail network.

ST will have to increase headways and reduce train speeds to complete the connection.

Patrick said that ST staff are still planning the construction work, and will announce firmer plans in January.