Truck noise from River Line DLRVs

Having rode the river line a few days back, I wonder if anyone here heard what appears to be a very loud banging noise comming from the trucks on sharp turns. Sounds like someone is smashing the car bottom with a large sledgehammer. Any speculations as to what that noise is? Or what is causing it?

I forget what that sound is exactly, but I believe that it has something to do with keeping the train from derailing that is installed on the tracks.

It sounds like the outer wheel is trying to turn faster than the inner wheel, but being solidly attached to the same axle, this is impossible. As a result, this sound occurs as the wheel skips along the rail.

That noise scared the heck out of me on my first ride (see my post). Thought the car was gonna derail. I can't believe NJT considers that acceptable (?) It sure doesn't inspire your confidence.

The noise sounds like a hinge to me. I hear it (very loud) when the angle between the end and center compartments is changing going into and coming out of a curve, but not when the curve is constant.

http://www.transitspot.com/gallery/New- ... _07_17_114