Shikoku's Anpanman Torokko Green Car
In addition to train rides, you can get special Anpanman breads and bentos (lunch boxes) along with plenty of exclusive merchandise. The train cars run various routes - the one that travels around Kagawa departs from Takamatsu in the morning before running two round trips between Tokushima and Awa Ikeda.
Trains run July through September, though not necessarily daily. JR Shikoku has a special Anpanman Train website, but it is all in Japanese and uses images for all of the text so nothing is translatable through Google. Seat reservations are available a month in advance and if you want to ride in the car above, I suggest doing it as soon as possible to avoid sellouts. As far as fares are concerned, the car you see above is considered a "Green" car and appropriate upcharges are applied. Advanced reservations are probably not required (they are available) for the regular Anpanman trains that run from Okayama to Kochi and Ehime - that is, unless you're traveling during holiday season.