by MBTA3247
I was discussing this with one of the other members at Seashore Trolley Museum (a retired T inspector) on Saturday afternoon. According to him, the switch at Beacon Junction defaults to the normal position (ie, straight thru for the C line) unless an outbound D train has approached it and the route isn't blocked by an inbound C train. Definitely a recipe for a speeding train to hit the switch before it finishes throwing and have the front truck go straight and the other trucks go left.
"The destination of this train is [BEEP BEEP]" -announcement on an Ashmont train.