Transverses

Transverse ride a perfect stone road that is believed to be thousands of years old.  The transverses are 8 to 14 feet wide, allowing two to pass eachother on the thirty-foot wide road that runs for hundreds of miles down the western crescent shore of Krahnis. The stone has been call Titanite, God Quartz, and Roadial Marble. It is unbreakable, resists known magics, yet produces no magic auras of its own. Millenia old, it shows no wear, remaining perfectly flat and level. The Unbroken Road of the Grand Traversal connects several ancient aged cities.  People travel along it year-round and small trade-oriented villages dot the edges.  But it is the world-renowned, massive "transverses" travelling on the perfect road that people always marvel at. These huge, ungainly-looking buildings on wheels are pulled incredibly fast by so few horses. Several use clockworks to pull them and travel faster than a horse as they need no sustenance and do not tire as a horse would.
Transverses are typically two to three story enclosed wagons, usually 15 to 30 feet long. Like rolling houses pulled by horses or oxens, these towering vehicles may be chained to one another forming trains. Their axles are often steel, but some use massive logs as axials. They have solid wood wheels usually a foot or more thick. Some old ones have a single granite cylinders around the axle.  Most of them have bases that are hundreds of years old, as the base of them contain a material that makes what is built and affixed to them incredibly lighter but does not create risk of toppling in the wind. The secrets of their construction and makeup is a closely guarded secret and a Transversal Engineer can be as wealthy as they like. It is commonly believed that moonglitter is the source of lift.  Moonglitter falls from the broken moon archipelago that floats in the southern sky.
The families that run them maybe be gypsy-oriented, always travelling up and down the coastal road, or straight-up companies of jarvies, transporting goods north and south. But like any such great vehicle, some have fallen into unsavory hands. Masquerading as merchants, rogues, robbers, and criminal figures use them as travelling bases of operations. 
The construction is typically wood, clay, stone, brick, crete , and daub. The insides are typically cramped with many features folding out or disappearing to make use of the limited space. Some stylistically have clay or thatch roofs, evoking the image of a well-heeled home. But more often the roof is and open area covered by trellises or cloth tents.  Gardens can be seen growing at the edges opened up to sunlight. 
Transverses can be bought, but typically would sell for several 100,000 GP, if you could find an owner that needed to sell one. Because of their value, most transverses are well armed and can be found racing down the road firing upon one another and attempting to seize a second one for their use.  But even criminals would not risk harming the lower chassis or wheels, as these can be irreplaceable when not near to a major city.