Police were informed of reports of a stabbing on a CTrain travelling north from the Erlton-Stampede Station around 11 p.m. Tuesday.
Police said a passenger activated the emergency stop inside the tunnel between Victoria Park and City Hall stations. This caused around 100 passengers to be displaced from the train.
Both northbound and southbound trains were stopped to ensure passenger safety and additional transportation was arranged.
Calgary police said the 26-year-old male suspect was quickly located and arrested. Charges are pending.
The victim sustained minor injuries, police said.
The investigation into the circumstances around the event is ongoing and police say it is unknown at this time if the victim and suspect knew each other.
Anyone with information regarding this incident is asked to contact police at 403-266-1234 or leave an anonymous tip with Crime Stoppers.
Calgary police said witnessing a violent attack can be traumatizing and that anyone in need of assistance should contact the Victim Assistance Support Team at 403-428-8389.