I was going to reference TORG but Jerry answered that much more thoroughly than I could have.
In general, if you have modern travel options and modern communication, it would be hard to have such totally different settings on a homogeneous world. You might have areas with preferences for one type or another but that would mostly be stylistic. In general people would end up using whatever is best for a specific situation and have a blend.
You could have religious or cultural reasons for the divides. Religious areas may be anti tech or anti magic (or both). However, I don't know if that would have enough different settings for you.
That leaves a TORG like world with different physical properties for different areas. In this case, figure out what caused it, how long ago happened, and which, if any, of the settings was the default before the incident.
The main question here is: do items from one area function in another area?
In TORG, people had a field around them that allowed the properties of their birth zone to overide the local zone enough to let personal devices work for them.
Maybe there is a sharp cut off where people have to get off the train, walk to another platform and board the lightning rail.
Maybe there are blended zones between or the zones are mostly blended areas with the bias stronger as you approach its center.
Maybe items from one area only function for a limited time in another area: batteries die, magic items slowly loose charges/power, robots experience increasing glitches.