Welp, another recovery goal has been met for the broke-down downtown-tunnel-boring machine: Bertha's repaired front end is now reuniting with the rest of its body. Seattle Tunnel Partners (STP), the state's contractor, started lowering Bertha's 2,000-ton cutterhead and drive unit into the rescue pit this afternoon—a complex positioning job that will wrap up tomorrow.

Once Bertha's new facial transplant makes its way into the pit, STP will begin reconnecting all of the machine's parts and test the monster for two months. These tests consist of a "no load" (read: no soil and water) exam and another exam that will measure how the machine's cutterhead spins into earth.

When STP pulled Bertha's front end out of the ground earlier this year, the contractor found that the machine had been damaged more extensively than previously thought. Workers had to replace the machine's main bearing, outer seals (which had nearly been destroyed), outer motors, and pinions. Last month, STP issued a new schedule showing the tunnel-boring machine restarting in late November of this year instead of August, as first promised.

Now STP expects to finish the tunnel in March 2018, more than two years after the project's original end date. That, however, assumes the machine doesn't get stuck again in the remaining 8,187 feet of its 9,270-foot journey.

I asked Chris Dixon, STP project manager, about that worst-case scenario. What happens if the machine does get stuck again—this time underneath downtown Seattle?

Dixon was short on specifics. "We'll have to do whatever needs to be done at that time from inside the tunnel," Dixon said. "But we're very confident with the repairs that we've made, and how well the repairs went, the extensive testing programs that we've got in place for October and November, that once we resume tunneling we'll successfully complete the tunnel drive without any further incidents."

Dixon also said that STP has not filed any new change orders over the summer asking the state to cover repairs. A now-dissolved Expert Review Panel estimated in April that change orders and other costs could tally up to $317.5 million, but that cost overruns could be avoided through insurance, contractor penalties, and spending less on rebuilding the waterfront. In May, a dispute review board found that the state was to blame for the steel pipe that blocked Bertha in December of 2013. The machine's been broken since that winter. The Washington State Department of Transportation says that the cause of the 2013 overheating and damage is still under investigation.

This post has been updated.