One of the key design elements of the AMRS modular layout is downtown Austin, Texas. We aren't modelling an exact point in time; the track plan is roughly based on the 1935 arrangement (see the CAD drawing below), though the buildings and rolling stock will mostly reflect the time period between 1950 and 1975.
Here is the track plan we're using to construct the Austin Downtown modules (click to embiggen):
You can compare that to this scale drawing of downtown Austin in around 1935, drafted by Vice President David Peterson. (Note the track plan is reversed west-to-east compared to this drawing.) SP (TNO) trackage in green, Katy trackage in purple, Mopac (IGN) trackage in blue.
Here are some documents that will be useful while building the new downtown modules, which have some differences compared to the original set of modules we operate:
For more information about the prototype railroads in Downtown Austin, check out this page.