these links and the one previously added should provide you with more information.
I met the couple at a bike festival tent set-up...seemed down to earth..and it is escorted.

http://www.firstclassmotorcycletours.com/

http://www.firstclassmotorcycletours...php?pagenum=11

 

no idea about the US trains but if the carraige the bike goes in is open be careful. About 8 years ago some friends of mine were going to a rally in the south of France, time was limited so they booked a sleeper train. Rode across the UK ,ferry to France and then a little further to put the bikes on the train .The French wanted to put the bikes on backwards, they explained the 3 road kings and a Heritage would get the screens blown off. A lot of argument later the bikes are on facing forward. They got up in the morning to find the train joint another in the early hours and their bikes are now facing the wrong way, no screens and a lot of damage.