My family loves the Rocky logo too Brad, an ageless and charming image that always brings a smile. We also like the IC's Piggyback Pig, happily rolling on his own pair of axles.
Santa Fe coined the term piggy-back for the service, and I think they copyrighted it. Which is why other roads talked about pigs, not riding piggyback, for several years. That said, Chico had a pig once upon a time...