Each segment is a folded from a single square of paper with no cuts or glue. The design is from a book I bought more than twenty years ago. It is all in Japanese, by Yoshihide Momotani. There are instructions for other types of train cars as well. The theme of the book is transportation, so there are also boats, cars, etc., but in my opinion the train is the best of what the book has to offer.
Perpetual Learner 