Patent ID: 7610862

Claim:
A rail road car truck for rolling motion in a longitudinal direction along cross-wise spaced apart rail road tracks, said rail road car truck having a load rating, said rail road car truck comprising: a bolster, a first sideframe, a second sideframe, a first wheelset, a second wheelset, a first spring group, and a second spring group; said bolster having a first end and a second end; said bolster being mounted cross-wise between said sideframes; said sideframes having upper regions rockingly mounted to said wheelsets, in operation said sideframes being operable to swing cross-wise; said sideframes being mounted to yaw appreciably relative to said bolster; said first spring group being mounted on a lower region of said first sideframe, and said first end of said bolster being mounted on said first spring group; said second spring group being mounted on a lower region of said second sideframe, and said second end of said bolster being mounted on said second spring group; each of said sideframes having a stiffness opposing cross-wise swinging thereof, k P ; each of said spring groups having a cross-wise shear stiffness, k SS ; when loaded to said load rating, k P being less than k SS ; said truck having resistance to yawing of said sideframes relative to said bolster; and said resistance to yawing of said bolster being a function of yaw displacement of said sideframes relative to said bolster; friction dampers and respective wear plates against which said friction dampers work when said bolster moves relative to said sideframes; and said first spring group has at least two rows of springs; and a single one of said wear plates is wider than said two rows of springs.