I would get my answer only minutes after wondering. As our flight continued, I saw something on the lines in the far distance, emitting a plume of smoke that gave away both it’s presence and the high speeds it was travelling at. My eyes widened slightly in genuine surprise when I saw what was using that metal-lined path: it was an enormous machine! A steam-driven vehicle moved very quickly along the special path, it’s wheels locked onto the equidistant metal lines and finally revealing their purpose as rails. A loud steam whistle sounded out as it passed underneath the sky ship, carrying the faint smell of coal smoke as it travelled. Strung behind it was a surprisingly large quantity of large, box-like carts that it somehow pulled along with ease under it’s power, each a little smaller than the vehicle itself and of a fairly uniform size. Each one was joined to the other in segments like a centipede, and had their own set of wheels anchored to those rails. The one at the front was a rail-cart full of coal, seven more had windows indicative of passengers, and the final nine were for transporting cargo, not dissimilar to how merchant vessels did.