I'll try and not go off-topic too much, but its a subgenre like Steampunk, just even lesser known. Steampunk usually has steam-powered devices, Victorian architecture/designs, and typically takes place in the 1800s, as you probably already know. Dieselpunk is 1930-1950s era technology, thus it has a more "modern" feel yet still has many of the odd devices and awesome vehicles. The best example of Dieselpunk is the movie Sky Captain and the World of Tomorrow
. Dieselpunk is often confused with Steampunk, though I'm hardly suprised that it is. Its slowly making its way into mainstream audiences though, like Steampunk.
The reason why I said Dieselpunk is because that red faction has a lot of features typically found in Dieselpunk, like a lack of dirgibles instead having jet engines keeping things afloat.