From Orly Sud train to Antony Ratp, RER to Paris Est, then train to Troyes. 2hrs 46min 43€. From Orly Sud bus to Rene Coty, line 62 bus to Gare Paris-Bercy, then bus to Arrêt OUIBUS Troyes. 3hrs 43min 10€. From Paris Orly Airport (ORY) drive to Troyes. 1hrs 44min 26€.