Federal police said they recovered 23 packages of the drug from the car after it crashed in the town of San Fernando in the northern border state of Tamaulipas.
The people being smuggled in a vehicle were from Honduras, Guatemala and Mexico.
They tried to cross the railway crossing before the train.
Pope Francis sent a note of condolences Friday to the families of the victims.
The crash occurred early Thursday in Encinitas, California.
Mexicans Daniela Ayón, 36, and Dora Isela Salas, 45, were on board of the Airbus A320 flying from Barcelona to Düsseldorf that crashed into the French Alps in March.
Mexicans Daniela Ayón, 36, and Dora Isela Salas, 45, were on board of the Airbus A320 flying from Barcelona to Düsseldorf that crashed into the French Alps in March.