Good article.
What he did not cover is that Lionel produced three distinct sizes of car to run on O gauge. Only one of them scale 1:48. As he mentioned, Lionel and other manufacturers, accommodated the need to be less expensive and to be able to turn on the corners most people would have room for by making units less than scale, ) 027 and traditional sizes with Std. O as their scale version. As they shortened the length of a car they also shortened the width and height to keep the same proportions as the prototype.
So a Std. O 40; box car is 10" long for the box. A traditional version is about 10" from the ends of the couplers ( not the box) and 027 is only about 9" on the couplers.
The widths are also impacted as stated above. If gauge in the prototype is only 56.5" but the train car can carry real automobiles, then the cars are much wider than the trucks of the wheels. Same as in Std. O, the scale version. On traditional, the cars are usually about he width of the truck and for 027, the trucks are wider than the box on top.
Scott
Scott Smiley