WI: Dual gauge railroads in America?

[Old1812]

Link for those wondering what I'm talking about: (https://en.m.wikipedia.org/wiki/Dual_gauge). Considering how dual gauge railways can join lines of different gauges, could this be used to create a more unified American rail network in the pre-Civil War period and the years following it? In a surviving CSA where the economy isn't quite a disaster, could this be a good workaround for their numerous gauges?

EDIT: While I know dual gauge was used in the US, I was wondering about giving it a much expanded role.

 

[sloreck]

The advantage the Union had was that rail gauge in the north was much more standardized at the beginning of the war, and became more so during the war. The issue with "dual gauge" in one sense is that if you are going to have only two gauges so you don't have gauges A & B in one place, B & C in another, D & A in another - and so forth - it becomes a disaster. During the ACW the problem was that the number of rail gauges in the south was a complete mess. At one point when troops from the ANV had to go from the east to Tennessee they had to change trains twice (three different lines) with incompatible gauges which, needless to say, caused a good deal of trouble.

Within a relatively short time after the ACW the only significant use of dual gauge was when you had interchanges between narrow gauge and standard gauge.