The series of black pipes currently jutting out onto Elm Street, coupled with the groups of construction workers toiling away this summer, means some big infrastructure projects are in the works for downtown Sudbury, one of more than 20 the city hopes to wrap up by winter. Brittany Hallam, the city's director of linear infrastructure services, said improvements to the city's water mains is the cause of the congestion, and the snake-like trail of pipe running along the sidewalks.