Last week's collision on the California Screamin' roller coaster occurred three months after Disney made major modifications to the braking system without consulting the ride's manufacturer.
State records show Disney changed two brakes in April – in the areas where a purple train passed through without stopping before colliding with a red train and sending 15 people to the hospital. The modifications were found to be safe by state investigators during a June 2 inspection.
But the ride's Swiss manufacturer, Intamin AG, says Disney didn't talk to the company about the changes, which is considered a good safety practice industrywide.
State investigators are still looking into the cause of the Disney crash. The braking systems in zones six, seven and eight – near the end of the ride, where the crash occurred – are part of the inquiry.
Disney declined to comment on the cause of the crash until the state investigation is done, said Rob Doughty, a Disney spokesman.
The brake modifications included relocations and the addition of "actuated eddy current brakes" in zone eight, and the addition of "passive eddy current brakes" in zone six. The purple car hit the red car in zone eight.