United States April 4, 2018 7:19 pm Silver Line Tunnel Closes Due to Crumbling Concrete The MBTA has closed the Silver Line tunnel until further notice after loose pieces of concrete fell on the inbound platform of the station. US & World Videos 2:31 Fallen Billerica Police Sgt. Ian Taylor honored at vigil 2:39 MIT president calls for shutdown of student encampments 0:16 4 people seriously hurt after boat sinks off Cape Cod 2:35 Fallen Billerica police sergeant honored during vigil 2:09 President of MIT calls for shutting down pro-Palestinian encampments