The collision occurred when one train slammed into the other at high speed, causing extensive damage and a large-scale emergency response.
More than 60 fatalities have been confirmed, according to officials, though the death toll could rise as rescue crews continue searching the wreckage.
Emergency teams are working at the scene, treating injured passengers and recovering victims from the damaged trains.
Authorities have not yet released a full account of what caused the crash or explained how the two trains came to be on the same track.
Investigators are expected to examine signaling systems, train operations and other safety procedures as they work to determine responsibility.
Further details about the victims, the number of injured passengers and possible service disruptions are expected as officials provide updates.