Construction work for the new downtown electrical substation project will cause temporary road closures starting Friday, June 12, as a new pedestrian bridge is installed over the Davis Mill Pond. Work will take place from 6 a.m. to 8 p.m. and the closure will be in effect 24 hours to minimize the construction time, Eversource spokesman Frank Poirot said. The schedule could be adjusted if needed. Once construction is complete on the new downtown substation on Railroad Avenue, at the former site of the Pet Pantry, the transmission line will connect it with the existing substation in Cos Cob. Many residents objected to the project for years, but Eversource says it is necessary to meet electrical demand.