I was reading a post on ken's blog where he cut up a toy car and modified it. http://model-railroad-hobbyist.com/node/5798

In it, he mentions that these cars are typically out of proportion.  I compared a few I have to some better quality cars I have and sure enough the toy stuff is higher.  My question is, how do I find out what the height on a typical toy car should be, if i wanted to tackle something like this?

Next month the old layout will start to come down and the proposed new, continuous running one will start to take shape. I have attached a diagram (first time working with this program so it is a bit rough) for your comments. The current point-to-point had a number of flaws in its operation and design. So, with the "acquisition" of some new space from my wife, who is being more than gracious since I agreed that a furnace, washer and dryer are essential, I now have a larger area. The new size is 12' x 5' x 30" deep around two support poles.