This new time-lapse video shows crews cutting and hauling away sections of the giant drill's rear over more than a month.

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Bertha’s time under Seattle is ticking away.

From the tunnel-boring machine‘s South Lake Union disassembly pit, crews have dismantled and hauled away the drill’s cutter head.

Now, they’re moving top to bottom, taking apart other sections and lifting them by crane, the Washington State Department of Transportation (WSDOT) reported Friday.

The disassembling work, led by tunnel contractor Seattle Tunnel Partners, is more than halfway complete, WSDOT said.

With the update, the agency released a time-lapse video from inside the Highway 99 tunnel, showing crews cut and haul sections of the giant drill’s rear back through the tunnel. WSDOT shot the images over more than a month.

Much of the machine’s trailing gear remains underground, WSDOT said. From both outside and inside the tunnel, crews will continue removing those pieces.

Meanwhile, they’re building the tunnel highway decks.

The four-lane, tolled Highway 99 tunnel will replace the aging Alaskan Way Viaduct and is expected to open by early 2019.

Bertha began its 1.7-mile dig from Sodo on July 30, 2013 as the world’s largest tunnel drill. A slightly wider machine dug a stretch of a tunneled highway to Hong Kong’s airport in 2015.

The machine in Seattle broke into daylight April 4. That was 29 months late compared to its original target date of October 2014.

Material from The Seattle Times archives contributed to this report.