Ottawa Paramedics say a 50-year-old man has died after having a heart attack while riding the Trillium Line O-Train Thursday morning.

The call came in at  7:58 a.m. from the Carleton-bound train.

Paramedics say other riders on the train started CPR when it happened, and the man was defibrillated by an A.E.D. on the train. Paramedics arrived on scene and performed advanced life-support treatments, but the man was later pronounced dead.

Ottawa Police and OC Transpo Special Constables are investigating.

OC Transpo suspended O-Train service for much of the morning, but resumed service at 11:30 a.m.