Rosa Esparza fell 75 feet to her death while riding the Texas Giant roller coaster in July at the Arlington park. The ride reopened in September.
The woman's family sued Six Flags and coaster maker Gerstlauer Amusement Rides in state district court in Fort Worth. Six Flags, which denied any liability, has now joined in the lawsuit against Gerslauer.
Kenneth Broughton, a Houston attorney for Gerstlauer, tells the Fort Worth Star-Telegram (http://bit.ly/1nIHQvB) the filing is a contract maneuver by Six Flags under its purchase contract with Gerslauer and is "pretty standard" in such cases.
Information from: Fort Worth Star-Telegram, http://www.star-telegram.com