A generic approach is essentially what I use. The structures are a general mix of old and modern and the vehicles range from the 50's to 05. By adding or subtracting vehicles and some small details of certain times, I can make the layout reflect whatever time period I want (in the time periods of the 50's to modern day) that I want it too. Still, it wouldn't be a big leap to have a train pulled by a team of F units or RS3's to come through town in 2001. Not likely to happen but it's possible.