Actually you can stack XyCraft tanks together, up. Meaning you make them max-wide, and the highest-evah! I love XyCraft tanks, I am gonna use them instead of RailCraft, mainly because they look nicer. Shame I literally wasted like, a ton of MJ and iron on that iron. But, yeah. XyCraft = The Best, ever. (Well, pretty cool. I really like ThaumCraft. Plus a few other mods. But it's really cool.)