Train+Train

Train+Train (トレィン☆トレィン Torein☆Torein) is a Japanese light novel series, written by Hideyuki Kurata (the author of the Read or Dream series) and illustrated by Tomomasa Takuma. A manga series was serialized in Dengeki Daioh between January 2000 and May 2003 and was completed by the sixth bound volume. The series is published in Japan by MediaWorks and for the English version,[4] the series' lettering is done by Team Pokopen and is licensed by Go! Comi.

Plot
On Deloca, a distant planet from Earth, high schools are mobile. They exist in train versions, huge ones, with shopping malls and dorms and anything else one would need in an education. Most students go to standard school trains, to travel around the world for a regular education.

Other Sources

 * Train+Train
 * http://www.animenewsnetwork.com/encyclopedia/manga.php?id=7493