The Department of Public Safety says the accident happened before dawn Wednesday just east of Amarillo.
Senior Trooper Chris Ray says an eastbound train rear-ended a stopped train, and that a westbound train then collided with the two-train wreck.
BNSF Railway spokesman Joe Faust says two crewmembers on the first train have non-life threatening injuries and that two from the second train are critically hurt.
Faust says the trains were hauling flatbed cars carrying truck trailers and that no hazardous materials spilled.