If I invited them, they get picked up. If a woman I’m sleeping with invited them, they get picked up. If they invited themselves, they take a bus.
I don’t see why it’s rude for them to take the train. I live in NorCal and my family lives in SoCal. I would travel to SoCal for Christmas by airplane to get to my brother’s house.
However, I feel like my brother is hosting and probably has things to do to get ready to host, and it is essentially my job to get myself to his house and not really his job to come pick me up at the airport.
I did have a few years when I did ask him to drive to the airport to pick me up (30-45 minutes each way), which he did. Then I got to thinking that he is trying to prepare for hosting the family, which isn’t easy, and I just robbed him of at least 60-90 minutes just by having him pick me up while placing the full burden on his wife to do all the hosting prep during that period my brother was away.
So, I started renting a car to drive myself between the airport and his house. If there was a rail line that was more handy than a car rental, I would take it upon myself to figure it out and take it to the nearest station to his house before asking to place a burden on him to cart me around town.
Able bodied guests taking the train doesn’t seem like a big deal; it’s just an extension of your guests’ travel to your place. I think they should do what they can to get themselves as close to your place as possible, if not all the way to your door, before asking you to help them travel.