Tags: home

Tunneling in Seattle started long before Bertha

Seattleites were digging tunnels long before Bertha, the SR 99 tunneling machine, came along. Folks started transforming subterranean Seattle in 1894, with construction of a sewer tunnel not far from the SR 99 tunnel’s north portal construction site. Since then the city has seen – or not seen, as the case may be – construction of more than 40 miles worth of tunnels.

Last month marked the 109th anniversary of the historic breakthrough on the Great Northern Tunnel, which still carries trains beneath downtown today. The breakthrough was scheduled to occur at 10 p.m. on Oct. 26, 1904, but tunnel planners didn't account for the fierce rivalry that had developed between the day and night crews doing the digging. Energized by the competition, miners digging from opposite ends of the tunnel punched a man-sized hole through the last remaining section of dirt at 5:55 p.m., five minutes before their rivals on the night crew could take over.

Back then there was nothing like Bertha to help these 300-plus workers build the tunnel. They dug the old-fashioned way, with shovels and picks, carting away soil in wheelbarrows and small rail-mounted cars. Timber scaffolding was placed to support the tunnel immediately behind the miners as they dug, then concrete walls were poured to line the tunnel.

Like the SR 99 tunnel, the Great Northern Tunnel was destined for the record books. On the day it opened, it was the highest (28 feet) and widest (30 feet) tunnel in the United States. The mile-long tunnel took about 20 months to complete. Today, it is operated by the Burlington Northern Santa Fe Railway, and is also used by Amtrak. If you’ve ever traveled by train between King Street Station and points north, you’ve been through this tunnel.

Bertha will dig beneath the Great Northern Tunnel during her journey beneath downtown. To find out when, check out our Follow Bertha page and learn about other cool things Bertha will encounter as she digs toward the north end of downtown.