NEB&W Guide to Period Modeling - Introduction
Scenery, Structures & Details Table of Contents
There are two approaches as to era. One is to avoid being specific. Some have suggested that a layout can be a time machine, so that with minor or no changes to the fixed layout itself, you can switch eras by changing rolling stock and engines. The other way to achieve this is to have a very broad time window, such as 1940's to 1980's. This is often the choice of the more casual modeler, who simply chooses items that appeal to them without regard as to whether these elements could have ever been seen at the same time.
The other approach is to EMPHASIZE the era rather than downplay it, deliberately modeling those items that give clues as to era rather than those that are era-generic.
In our culture, as in any, there are certain technological advances that are so total and sweeping in their acceptance that they give a watershed. For example, if you were watching a movie about newspaper reporters, the news room would either contain typewriters or computers, setting the era as either pre-1980's or post. Other changes include horses vs. autos, and of course, steam to diesel. My point is that these watersheds take place at different points.
On the other hand, while we as railroad modelers can model any segment of geography, we naturally tend to model that which surrounds and relates to railroads. The way railroads relate to our everyday lives has passed through a watershed, corresponding somewhat to the steam-diesel transition. But this also relates across all of our society, because the railroad was supplanted by the family car. Downtowns are no longer crowded with middle-class shoppers, viable stores are in malls or mini-malls, always surrounded with parking lots. The typical depot today would either be torn down or converted to an antique shop or ice cream shop.