The tunnel still under construction under Seattle could be open by Thanksgiving 2018.

However, the current official timeline is early January 2019.

The Washington State Department of Transportation and Seattle Tunnel Partners, the consortium of contractors, provided an update Thursday on tunnel progress, which is proceeding rapidly since Bertha the troubled tunneling machine finally broke through at the north portal on April 4.

It took four months to dismantle and remove Bertha. Meanwhile work inside the tunnel building road decks, ventilation shafts, even erecting some signage at the north end of the project has been progressing.

"Our schedule right now is to achieve substantial completion by October of next year," said Chris Dixon, who heads Seattle Tunnel Partners.

"We're holding to a January 19 opening, with a commitment to try and advance that forward," said Joe Hedges, WSDOT's administrator for the tunnel project.