You provide some interesting information.
I am interested in what you use for a setup to make your cuts when you slice through a car body. The Dremel saw has a depth of cut of 1". Which is less than the thickness or height of an HO house car. So you have to make at least 2 passes. And I assume you have to do some repositioning. My whole reason for suggesting using a larger saw was to eliminate repositioning of the part and possible consequent inaccuracies.