The "sand steamer" is a steel monstrosity. There are no oceans on this dust bin of a planet, of course, so it does have wheels, but its shape—at least the shape of its lower half, where passengers stay for the trip—is very reminiscent of that of an upside-down cruise ship, the base wider than the top, with three rows of small windows peering out of the individual cabins inside. Its upper half, however, supports an enormous laser cannon as long as the ship itself, nominally meant to clear obstacles and to serve as a defence against the larger and more aggressive kinds of worms, who often hunt in packs out in the middle of the uninhabited desert this contraption travels through, aptly named the "Great Sand Ocean". The port they'll be embarking from has three long metal bridges extending towards it for passengers to board, leading onto the deck; below, large crates of cargo are being loaded and unloaded.
This ship isn't exactly a cruise liner, but it's not exactly not one. Its outside is as dusty and ugly as everywhere else, but inside one can find a measure of comfort and even luxury, as the main patrons are rich people wishing to travel between the Seven Cities without having to brave the dangers inherent in using baser forms of transport such as cars or birds. That said, there are slightly less exorbitant tickets that give you access to a cot in a communal room shared by dozens of others. The competition for these tickets is fierce, and it's mostly people who want to escape their little nowhere towns to make a living in the city and who have gotten some unexpected windfall—or who have been saving for a long time—who actually get those.
But most interestingly, these ships are powered by plants, and the ports it stops at between the Cities often don't have their own plants, so the arrival of a steamer can often mean a large influx of goods that these towns would otherwise not have any access to. It goes without saying that powering an enormous vehicle and providing people with plant resources is hell on the plants; this specific ship has gone through two of them already since it's started operations and this third is likely to get into red state soon.