railroad gauge

Hi-
An amazing variety of railroad gauges have been used by USA railroads. They have been as small as the 1 foot gauge of the Sonora Short Line to the 6 foot gauge used by the Erie and Lackawanna, Erie and Great Western and the Ohio and Mississippi
I'm compiling a list of all gauges used by USA railroads, both in the past and present. I know of 17 different gauges which have been used.
The widest current gauge I am aware of is BART, at 5 ft, 6 in. The narrowest was The Hunt System (wherever that was), which used a 2 ft, 9 1/4 inch gauge. Other than that system and the Sonora Short Line, I know of no systems with gauges under 3 feet.
However, it seems to me that the gauge of the Victor and Cripple Creek Railroad is less than 3. If you know what that gauge is, or of other gauges less than three feet, would you let me know.
Just as an editorial remark, what do you think of including the gauges of amusement park rides and zoo rides, such as the train at the Omaha Zoo?
Thanks- Bill Ramaley