Disassembly reveals the inner workings of the SR 99 tunneling machine

In this June 2017 photo, disassembly is revealing the complex inner workings of the machine that completed a 9,270-foot tunnel beneath Seattle this spring. Learn more about the Alaskan Way Viaduct Replacement Program at www.alaskanwayviaduct.org or follow us on Twitter @BerthaDigsSR99.

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