Complex sentence: As a result of the new system, multitrip tickets are no longer be sold as Crouzet tickets, instead MetroCards must be purchased to replace them, and Seniors tickets have been replaced by the new Seniors Card.
Split into simpler sentences: As a result of the new system, multi-trip tickets are no longer sold as Crouzet tickets. MetroCards have replaced them, and Seniors tickets have been replaced by the new Seniors Card.