An experimental propulsion system installed aboard the Starfleet vessel USS Miyazaki, whose catastrophic failure killed the crew and left the ship a derelict later used as a training ground for cadets.
The singularity drive was an advanced experimental engine tested aboard the USS Miyazaki. When it was activated the system failed disastrously, the whole crew died, and the ship was left adrift for more than a century.
The drive features in the Starfleet Academy episode Come, Let's Away. Cadets from the Academy and the War College board the wreck for a joint exercise, with Chancellor Nahla Ake explaining its history, and are then trapped when the hostile Furies seize the ship and raise a jamming field. Caleb Mir and the cadet B'Avi manage to restart the old drive during the crisis.
The idea of drawing power from a singularity is older in Star Trek: Romulan warbirds of the 24th century used an artificial quantum singularity as their power source, as seen in The Next Generation.