Just as Bertha is stuck under downtown Seattle, the state’s residents are stuck with Bertha.

Bertha, at 900 tons and 57 feet long, is the world’s largest tunnel boring machine and is tasked with burrowing through the uncertain soils near the Seattle waterfront. Upon completion — assuming completion — its cylindrical tunnel will support two road decks that will carry the vehicular traffic that now sails overhead on the elevated, doubled-decked Alaskan Way Viaduct, which is slated to be torn down.

The tunnel’s plan was for traffic to flow through it at the of 2015, but that date is on hold along with the machine. The next best estimate is mid-2016, and that’s assuming that fixes can go smoothly on Bertha, the namesake of 1920s-era Seattle Mayor Bertha Knight Landes.

Bertha the machine had drilled just over 1,000 feet of the projected 9,270-foot tunnel when it overheated and stopped suddenly on Dec. 7. It suffered damage to its cutting blades after striking a steel well casing left over from decade-old drilling done by the state to assess soil and groundwater conditions. Repair workers found sand in the grease around the main bearing and determined that all seven rubberized seals protecting the bearing must be replaced — and the bearing itself may need replacement along with other parts of the machine.

Repair work will require digging a deep pit — Bertha is 60 feet below ground level — to get access to the front of the machine. The tunnel’s project manager now is hoping for a Sept. 1 date for restarting the tunneling, and that date is considered optimistic.

Bertha the mayor inhabited the political realm, and so it goes with Bertha the machine, which is the centerpiece of the state’s Highway 99 megaproject. The debate about a viaduct replacement intensified after the Nisqually earthquake of 2001 seriously damaged the structure; Gov. Chris Gregoire and Transportation Director Paula Hammond made the controversial call to replace the viaduct. Now, Gov. Jay Inslee and Department of Transportation Director Lynn Peterson have inherited the tunnel and its problems, and they are quite aware that it’s up to them to troubleshoot this troubled project.

The immediate question is what this means to the project’s cost and to taxpayers who are already weary of state DOT bungling of other projects approved by the previous administration, especially the leaky pontoons for a floating bridge replacement on State Route 520. The state DOT’s problems contrast with the so-far smooth work by Sound Transit on a 3-mile-long light rail tunnel between downtown Seattle and the University of Washington. The tunneling is finished, and the extension of the current light-rail line is scheduled to open in 2015 — under budget and six months ahead of schedule.

As for Bertha, the issue over the leftover well casing already had strained relations between the state and the consortium building the project, called Seattle Tunnel Partners. News reports now say problems with the seals were found when the Japanese company that built Bertha, Hitachi-Zosen, tested the apparatus before it was shipped from Japan. The question is even arising as to whether the project can be completed.

The project, with an estimated cost of $4.25 billion, must be completed. We are too far down this road on a project that is so important to the state’s transportation network — especially freight mobility — to take a detour now. It’s up to the private contractors to work out these serious problems, and it’s up to the state to make sure they do.

• Members of the Yakima Herald-Republic editorial board are Sharon J. Prill, Bob Crider, Frank Purdy and Karen Troianello.