Taking apart an 8,000-ton, five-story machine sitting partially underground offers no quick task. Bertha, the tunnel-boring machine that recently completed a 9,270-ft tunneling journey underneath downtown Seattle has reached the halfway point of another milestone: disassembly.

Contractor Seattle Tunnel Partners continues to remove the machine, which saw its cutterhead located in the disassembly pit and the rest of the machine trailing behind into the tunnel it created.

At this point, all of Bertha’s cutterhead has been removed from the disassembly pit near the Space Needle at the north end of the tunnel and crews continue working from top to bottom to cut sections of the machine and lift them out by crane.

Much of the machine’s trailing gear remains inside the tunnel, out of view of WSDOT time-lapse cameras. Inside the tunnel, crews continue cutting and hauling pieces of the trailing gear out of the tunnel via the south portal. Project owner Washington State Dept. of Transportation created a new time-lapse video to show the work happening inside the tunnel, which puts a focus on the back end of the machine.

Watch the 30-second video here.

Work has progressed enough inside the disassembly pit to allow Seattle Tunnel Partners to use Bertha’s thrust rams to pull large sections of the trailing gear into the pit. Crews can now work from both inside and outside the tunnel to remove the gear, which officials say will speed the work.

Much of the conveyor system that once extracted Seattle’s soil from the tunnel machine and moved it toward barges has already been removed.

While a focus remains on the dismantling of Bertha, the highly publicized machine, work plods forward on the piece of the multi-billion-dollar project that travelers will encounter: the roadway. Work progresses on the southbound and northbound walls as crews ready the double-decker roadway for opening in 2019.

Follow Tim Newcomb on Twitter at @tdnewcomb.