On November 7, 1916, a streetcar loaded with passengers ran off the open Summer Street Bridge, a 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.

[2] At 5:13 pm on November 7, 1916, Car #393 began an inbound run from City Point with motorman Gerald Walsh at the controls.

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.

[2] Walsh, McKeon, and around fifteen passengers managed to escape the car and were rescued by tugboats and passing pedestrians.

Some questioned how the glass lantern had survived the impact of the trolley with the gates, which broke a 4-inch (100 mm) iron post in two; they alleged that the bridge tenders may have actually hung it after the accident.