UPDATE: Victim identified as Hyde Park man.
An Acela train barreling through Hyde Park station struck and killed somebody around 10:30 p.m. The engineer immediately applied emergency brakes, but it still took several blocks for the train to come to a stop - just on the other side of the West Street bridge, well north of the station.
More than 100 passengers sat on the train for more than two hours beside beside a wall painted with "Welcome to Boston," while outside, police and firefighters also waited, to help transfer passengers to a promised relief train from South Station that never came.
"The train crew haven't announced what happened, but passengers told them we read about what happened on Twitter," Jesse, a passenger on the train reported.
He added that the train "coasted to a stop with a burning electrical smell that I presume was the brakes. AC was off for a few, then kicked back on."
At 12:45 a.m., after an inspector took one last look around the train, the engineer sounded its horn twice and the train took off for Back Bay and South Station.
Meanwhile, back at the Hyde Park commuter-rail stop, investigators continued to examine the tracks and put down evidence cones along the inbound platform. Three white tarps covered remains along the center tracks.