ATLANTA — A woman was brutally stabbed to death in a senseless, unprovoked attack aboard a MARTA train Saturday afternoon, the second stabbing on the troubled transit system in less than a week.

The nightmare unfolded around noon at the Oakland City Station in southwest Atlanta. Witnesses said a man suddenly attacked the woman on the train before it pulled into the station, plunging a small knife into her as horrified passengers looked on.

MARTA police officers patrolling the platform rushed in, immediately cuffing the suspect and trying desperately to save the victim. Medics worked on her on the platform, but she was pronounced dead at the scene. A dark object consistent with a pocket knife lay nearby on the ground.

Shocking cellphone video from the chaotic scene shows the suspect face-down on the platform as officers swarm the area, with bystanders and transit workers standing nearby. Rail service was halted, forcing shuttle buses between stations.

“This was a senseless act of violence,” MARTA officials said, expressing sympathy for the victim’s family and traumatized witnesses.

No names have been released for the victim or the suspect, who remains in custody. Police have not disclosed a motive, describing it as a random horror that left riders shaken.

The deadly attack comes just days after another stabbing at a MARTA station, sparking fresh outrage over safety on the system as Atlanta gears up for major events, including next month’s World Cup matches.

Riders voiced their fears online and at stations, with many blaming lax enforcement and “free riders” for turning trains into rolling danger zones.

“When is enough enough?” one frustrated commuter asked. “People are scared to ride MARTA now.”MARTA police vowed a full investigation and promised increased presence, but for Atlanta transit users, the latest bloodshed is another grim reminder that public safety on the rails is hanging by a thread.