Detective Jack Russell says the man boarded the LRT at the Sunnyside station around 7:45 p.m. Tuesday.
He tried to rob another man, but three other transit riders confronted the crook, undeterred by a knife and can of bear spray he waved at them.
They were able to disarm and subdue him until police got on scene.
Russell says the man was taken into custody and multiple charges are expected to be laid.
No one was injured during the incident.
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