Wheelchair kinda bikes and trains

Just had a chat with someone on a wheelchair.
They were wondering how this kind of a caravan structure might be pulled by them.
Showed them Rosie’s Swale Pope’s book, “just a little run around the world”, for an example of something similar yet different

Somehow the chat veered off towards moving between cities. They said trains are not very useful. They have a special bike made – and a few times they were not allowed on trains with the device 🙁