The Summer Street Bridge disaster occurred on November 7, 1916, when a streetcar loaded with passengers ran off an open drawbridge into Fort Point Channel near downtown Boston, Massachusetts, United States. Forty-six passengers were killed, making it the deadliest disaster in Boston's history until surpassed by the Cocoanut Grove fire in 1942. By 1916, the Boston Elevated Railway (BERy) operated all streetcar and rapid transit lines in Boston. Original plans had called for an elevated rapid transit loop line through South Boston; however, that line was never constructed. Instead, South Boston was served by a network of surface streetcar lines that connected to the rapid transit lines at South Station, Broadway, and Andrew Square. The line from City Point to Washington Street served many industrial workers who worked along East First Street and Summer Street in South Boston. It ran along Summer Street for most of its length, crossing the 1899-built Summer Street Bridge over Fort Point Channel to cross into downtown Boston. The retractable bridge has two sliding sections of roadway – one for inbound lanes, one for outbound – that can move away from the bridge at a 45-degree angle to create a channel for ships to pass. At 5:13 pm on November 7, 1916, Car #393 began an inbound run from City Point with motorman Gerald Walsh at the controls. The car was an extra, operated to fill a gap between scheduled service. Walsh had not worked the City Point route before, nor had the conductor George McKeon, but both were familiar with the area. Car #393 was a typical 1900-built streetcar, a workhorse of the BERy fleet of the day. As it approached the Summer Street Bridge, it was full with around sixty passengers on board. The bridge was in the midst of opening to allow a ship to pass; the inbound roadway was already slid to its furthest position. Walsh failed to obey a small stop sign located at Melcher Street, though he slowed for a boarding passenger. Walsh noticed the open bridge too late to stop; the wheels locked and the streetcar crashed through a set of metal gates and into the channel.