Given that MARX, Lionel, and American Flyer factories were all within the service areas of Pennsylvania Railroad as back in the first half of the 20th century was the bulk of America's population so I rather think that this rubbed off on the train model train makers of the era as this is what most people saw day to day along with NYC and has just coasted along into the 21st century. Other railroads got pretty good coverage as Santa Fe did as it not only was familiar to those of us in California but to kids living in the east as the adventure of the cowboy west. So those three names appear to be the most popular of that era. May have also had a lot to do with the placement of dollars to the model train makers as an advertising investment.
Bogie
