Almost all of the Autorack trains I have run over the Sandpatch grade develope this "porposing" or couple lag snap as you run down the grade. Sometimes this can result in a 5-6 mph swing in mph from low to high as you are going downhill. It only appears to happen in Autorack Car trains. I think I remember something about Autoracks having long draw or cushion couplers but am not sure Does anyone know how to mitigate such behavior. Once I reach the 50 mph territory it mostly stops but on the steeper grades its pretty constant.
