Mechanical Department "No no that's fine shove that 20 pound set all around the yard... those shoes aren't hell and a half to change..."
The Missabe Road: Safety First
You may want to try your question over on the model railroading forums. But my understanding is it is a technique where the plywood (or your material of choice) for the track bed is visible the rest of the bench work is open. This way you can vary the elevation of the "landscape" below/above track level.
But post over on the Model Trains benchwork forum and someone may be able to give a better description of cookie cutter layout.
J.P.
This question was already answered for them.
Thanks though guys.