Both previous answers are incorrect. While touring, Trans-Siberian Orchestra are 2 bands performing the identical same show. In 1999 the first year Trans-Siberian Orchestra toured it was the only year they toured as one band. Do to the demand and since they play Christmas themed music they have a small window of time to tour. In 2000 they divided the original band and added members to each to create 2 touring bands. Each band has members from the original band which appear on the CDs. The 2 bands are known as the East Band and the West band. And believe it or not there is actually a 3rd band that stays in NY city and is ready to perform at a moments notice. This is the back-up. TSO has never canceled a scheduled show. If any one can't perform a back-up is brought in. How do I know all this? I go to many TSO shows a year and have been since 2000.