<br><br>Although it doesn't apply now (no humping in.Roanoke) when cars were.humped they rolled thru several retarders which applied pressure on the sides of the wheels, thereby scrubbing any sediment on the wheels..<div id="yMail_cursorElementTracker_1735247054301"><br><div id="ymail_android_signature"><a id="ymail_android_signature_link" href="https://go.onelink.me/107872968?pid=InProduct&c=Global_Internal_YGrowth_AndroidEmailSig__AndroidUsers&af_wl=ym&af_sub1=Internal&af_sub2=Global_YGrowth&af_sub3=EmailSignature">Sent from Yahoo's Mail osntn Android</a></div></div>