A little background here. First, Yes, the Erie and affiliated roads were built to a guage of six feet and continued so into the 1870's. At the same time, there was a 3 ft. gauge system that ran all the way from Toledo and Cincinnati, Ohio. to Houston, Texas!
One of the many reasons for "the late unpleasantness" was the fact that the majority of the railroads in the North were built to a gauge of 4'8.5" while those in the South were built to a gauge of 5 ft., resulting in traffic moving for export rather than between regions. Gowan and Marx of Charleston, SC, were invited by the Czar of Russia to build the first Russian railroad, so the Russian system were built to the Southern gauge of 5 ft.! It was the 1880's before most of the lines in the South were regauged.
With the invention of electric railways, a gauge of 5'2.5" was used by electric lines in many areas. As a matter of fact, the lines in Philadelphia, Pittsburgh and New Orleans (St Charles) are still 5'2.5". This, also, is the "broad gauge" referred to originally in the question about triple gauge track in the Cincinnati area.