Of the thousands of visitors who will immerse themselves in the rich heritage of Alexandria, Va., this summer, only one will have the job of helping the city just south of Washington, D.C., make some history of its own.

The new arrival is a 380-ton tunnel boring machine (TBM) that will play a key role in Alexandria’s largest infrastructure project to date—the $665-million RiverRenew initiative to remediate longstanding combined sewer overflow (CSO) issues and improve the quality of city waterways.