a deformable connecting interface between the axle and the guide arm which, because of a deformable nature, facilitates {TAIL ~ lateral displacement} of the axle relative to {HEAD ~ the guide rail} ; and 
a deformable connecting interface between the axle and the guide arm which , because of a deformable nature , facilitates { TAIL ~ lateral displacement } of the axle relative to { HEAD ~ the guide rail } ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH