Let's keep things rolling in the accident department with...
http://news.bbc.co.uk/2/hi/uk_news/8197231.stm
It's not clear though video, pictures or reports if 2 trains collided, which I find pretty unlikely, or if a train separated and then the train parts collided later on in the ride. I've heard of that happening before. At least twice on American eagle though both times were fairly minor then at Geauga Lake I think Big Dipper did that in the past in a more catastrophic nature similar to what may have just happened at BPB.
I'm lead to believe the latter as it is a weekday, so the crowds at BPB probably weren't enough to warrant 2 train operation, which I'm not sure they really ever do on Big Dipper. Also usually on 2 train operation coasters they wait til the previous train gets to the final brakes before releasing the newly loaded train, or at least they don't release the train in the station until the train ahead of it is at a spot where the train can be stopped on the lift if anything happens to the train ahead of it.
Either way it's not good, though at the very least this year's wave of mechanical malfunction ride accidents/incidents haven't lead to any fatalities.
actually...update... I'm not going to delete what I said cause i'm still not 100% sure, but I've now seen pics from different angles, and I can see at least 2 cars on elevated track, picture cuts off after that, then in a different pic again I see at least 2 cars at ground level before the pic cuts off again. The ride runs 3 car trains. Pics could have been from different times after they moved stuff around or whatnot, but still, it may very well be 2 trains actually colliding, which I find inexcusable.