MisterImmortal
The city is so big already and the world is getting completely connected, so why not introduce trains, metros and railroads? It can solve the problems of flow of people and resources, it can also be a way for fire and lighting-release shinobi to earn a living, by creating energy for the grids and the furnaces of the trains. Just need to say Nidama Clan's members managed to develop the technology after years of research. ;D