Of course, some people like fluff - witness expensive rulebooks laden with fluff sold by GW and Privateer Press for example. And I admit, it can be nice to leave this part of gaming to someone else. World building can be exhausting!
You really don't need that much info though to stage a game. You do need to consider what level of technology you want in the game though.
So, maybe you want :
- Only land vehicles.
- Only what was available historically.
- Vehicles that can fly.
- Vehicles to be in the early stages of development and more than a bit temperamental
- Technology to be well established and reliable.
- Technology that is prolific.
- Advanced technology limited to the imperial powers.
- Advanced technology limited to the invaders of Earth.
- To buy a few Warmachine warjack minis but don't want to invest in the rules and building a particular army, so a set of rules that can handle steam powered robots would be handy.
Whether you want to fly around the world in 80 days, investigate the fauna 20,000 leagues under the sea or well, I can't think of any book titles obviously about steam power, the table for vehicle generation has you covered for speed values with respect to Steam, Sail or Swim power.
Vehicles and conveyances can be made more or less reliable simply by playing with the Start and Sustain values. Eliminate them entirely if you think the technology is perfectly reliable. That said, even the most modern of automobile engines run into trouble now and again, so maybe assigning a very low value to Start (and Sustain) is more realistic (that said, realism is hardly the hallmark of G.A.S.L.I.G.H.T.).
Never underestimate the immersive effect of the hatred one develops for a piece of hardware that won't start. It's quite amazing, given that, in my case at least, they are made of cast-off materials cobbled together roughly.
To represent armor, G.A.S.L.I.G.H.T. vehicles have Save values. So maybe that steam powered robot (Ok, its not a vehicle but it has vehicle like characteristics) has incredibly thick armor (and a high Save) but the mechanical rats of Dr. Nym have poor armor with a consequently low Save.
Although the rules cover randomly generating your vehicles characteristics, assigning them on a WYSIWYG basis makes more sense, at least for weapons. I prefer to be able to look at a model and know what it has, rather than referring to a vehicle sheet. I also game under the unsupported belief that walking vehicles pivot poorly (as the technology is in its infancy), while vehicles with treads pivot easily (45 vs 90 degrees respectively) and so I assign this as well.
A similar have-it-your-way approach applies to fantastic weapons by the way - although there is no reliability or save factor. This is easily added though if such things are important o you. G.A.S.L.I.G.H.T. doesn't break easily under the weight of house rules, in my experience at least.
So you can add "Reliability" to your Magnetic-Hydro-blaster, to be tested each time you use it, and if you fail, figure out what awful things might happen - be sure to include everything from the likely to the hilariously improbable. G.A.S.L.I.G.H.T. truly let's you realize your vision of an alternate past.
Up next: the much maligned, but terrifically fun in my opinion, G.A.S.L.I.G.H.T. approach to failed morale checks