The Houston Police Department confirmed the incident happened at about 3:15 p.m. at the intersection of Old Spanish Trail and Greenbriar.
METRO police said the incident unfolded when two vehicles were involved in a crash, which sent them into the path of an oncoming Red Line train.
That train then reportedly hit at least one of the cars.
In total, police said four vehicles were involved, plus the METRO train.
Authorities said six people were taken to the hospital to be treated, though the extent of their injuries is unclear.
Police are investigating what caused the initial collision.