Road crews are halfway finished unearthing and replacing Civil War-era sewer and stormwater lines at one of Bangor’s busiest downtown intersections. “We’ve tried our best not to disrupt anything. I think the worst of it is over,” Public Works Director Dana Wardwell said of the work, which began in April and has at times narrowed travel on Exchange, State, Harlow and Hammond streets to one lane, and led the city to temporarily reconfigure Park Street to one-way traffic. The roadwork, which is expected to wrap up in October and November, is the most substantial project Bangor Public Works will complete this year, and is a continuation of a larger endeavor that began last October, Wardwell said.