I'm not familiar with them, but I believe they are Warhammer Fantasy designs...
The scenery behind the models (cobblestone road and masonry type walls on the buildings) as well as the overall "steam punk" sort of design also is quite telling, note the steam piston on the side of the mortar-like one, as well as the "coupling rod" on the one with the cattle-catcher attached to the front.
If I had to guess, I'd think they were Dwarven in design, but the flashy red does make one wonder about orc influence... But why no painted on skulls and attached pointy bits and parts that "mak eet go fastah"? All in all they seem to be too clean and well maintained to be original orc works, perhaps captured and repainted? Or maybe just a Dwarven unit that digs red and gold/yellow?
Still neat though!