Yes, they are still investigating the accident. DOSH (Department of Occupational Safety and Health) is very meticulous about this stuff and Screamin' will not open until A) they have finished their investigation, B) they have issued to DLR what caused the accident and what DLR needs to do in order to prevent it from happening again, and C) DLR implements their recommendations to DOSH's satisfaction. This is going to take months. I do know that they have been doing tests on the particular brakes that failed to stop the purple train after the camel hills going into the helix by running one of the undamaged trains through the ride while filled with dummies. At the very least, that set of brakes and the sensors nearby will likely have to be replaced. They might have to replace all the brakes and sensors.
Because this accident was caused by a mechanical failure, it's going to probably take longer than an accident that was caused by operator error. The only incedents where the rides tend to reopen within a short period of time are the ones caused by guest stupidity--iow not keeping hands, arms, feet and legs inside the car, train, boat, etc... or when someone had one of the conditions listed on the warning signs and shouldn't have been on the ride in the first place.