Aqueduct Railway Interconnection System or ARIS is the mass transportation system which is connect major cities all around the Sungear Republic. Eleveated 20 meters above the ground, it's inspired by the ancient water bridges of the same name. It combines the mass rapid transit and industrial transportation into a single network, meaning that the people in the metropolis can visit the border city back to back within a day on a single train.

ARIS was introduced 200 years ago. At first many system were built seperately before it's been centralized.