The rear suspension on many vehicles has one side's shock absorber pointing forward, and the other pointing aft, to promote the same basic softening action as the angled cuts would produce. (And a railroad crossing was used in the original article on Fords I'm recalling, lol.
And aren't RR crossings designed at angles when possible today for the nearly the same reason?)(they have to maintain the crossing, less traffic pounding = less maintenance)
Near stall, the resistance of two offset ruts and an axle with slight fore and aft play/twist make it a smooth "climb" of half steps, with some forces becoming lateral rather than both wheels doing one simultanious big step which tends to produce a violent vertical hop.
It might be mentioned, I kinda just scanned this thread, but think the real RR offset rail connections too. Weight vs joint intergrity plays a bigger role I'd bet, but smooth doesn't hurt...."you can sleep" 
