Despite being for the most part at a 1600's level of technological development, the Empire of Warhammer Fantasy Battle has METAL BAWKSES as well. They were actually invented by Dwarfs with collaboration from the founder of the College of Engineers himself, the famed Tilean inventor and Engineer Leonardo da Miragliano (a reference to real life genius Leonardo da Vinci (blessed be his name)), and thanks to the alliances between German and Scotsman in Warhammer Fantasy, Humans ended up with the plans. Dwarfs refuse to use anything that hasn't been tested in the shop for at least a few hundred years before the first field test (although newer generations of Dwarfs are rapidly using newer and newer creations, which pisses off the older Dwarfs to no end. The fact there's fewer old Dwarfs to beat them senseless for showing "Elvish Sense" may have something to do with it...) so these tend to only show up as scenario options for them or as proxies. The general design may have been simplified for the Deathroller in Blood Bowl that Dwarf teams bring though.
Only twelve were built and only eight remain to this day, the secrets behind their construction lost following Leonardo's death.
As one would expect, they're usually covered in symbols of the Empire. Griffons, skulls, Germanic flags, wreaths, and crossed muskets. 40k fans are tsundere for them, partially because after decades of seeing Rhino after Rhino the design for the Steam Tank of the Empire is a glittering prize (to say nothing of the MANLY mustache and glorious METAL hat sported by the man on top who wants to hit things with his JEWELED sword). On the other hand, anything that isn't Warhammer 40k is heresy so they can't like it. Oh well!
On The Tabletop
There's nothing else to say except get as many in your army as you can.
Originally, Warcraft III had a heavily armoured siege unit called the Steam Tank for the Human Alliance faction. In-game, the unit is known for trolling other factions hard by just spamming the damn thing. Due to its heavy armor and high siege damage, spamming these toys can make your opponent rage about humans being OP. Thankfully, it can only attack buildings.
However, its name and design (along with the Gyrocopter) were changed by Blizzard for the expansion and World of Warcraft, quite possibly as a result of being threatened with having large stacks of papers being thrown at them by GW's lawyers. They are henceforth known as the Siege Engine and Flying Machine.
The US government experimented with this idea in 1918, building a functional prototype with a 370kw engine armed with a flamethrower, but ultimately turned it down. Internal combustion engines have an edge in power to weight ratio and did not need time to get fired up.
Other than then that, the Steam Tank is actually a reference to one of the infamous Leonardo Da Vinci's turtle tank blueprint. After all, Steam Tank IS invented by Leonardo da Miragliano, whom the character itself is a reference to the real life Da Vinci himself.
The closest the Empire has ever come to victory over the Wood Elves.