I want to book the Texas Eagle from Chicago to San Antonio. When I went to Amtrak's site I see 2 trips for my date Oct 6, 2023, one #21 is sold out for the rooms and the other is #421. They have the same price, the same times, and the same route as far as I can tell. Am I missing something or are they the same, or can I just book the #421 with no worries? Why are there two? They both can't depart at the same time, can they?