I think you just start one up yourself? I have joined the Friendship Train. Looks like everyone who replied was added to the list. The theory is you follow everyone on that particular list and support each other. It has to be updated as others join. But someone has to be responsible for that list.
https://steemit.com/friendtrain/@infobunny/the-steemit-friend-train-has-been-updated-19-06-2017 check it out, my name was added at the bottom