9781422284827
This is the emergency tunnel dug by Seattle engineers to reach the tunnel-boring machine that needed repairs. Once that was done, Bertha the tunnel-borer soon was hard at work!
10
Made with FlippingBook - Online magazine maker
This is the emergency tunnel dug by Seattle engineers to reach the tunnel-boring machine that needed repairs. Once that was done, Bertha the tunnel-borer soon was hard at work!
10
Made with FlippingBook - Online magazine maker