How was the expansion of railroads in South Carolina different from the expansion of railroads in the rest of the United States?

In South Carolina, the expansion of railroads after the Civil War was much quicker than in other areas of the AUnited States.

BRailroads throughout the United States were built with a standard gauge, or width, except in South Carolina, where varied gauges were used.

CIron rails were used in South Carolina when building new railroads; steel rails were used throughout the rest of the country.
D
After the Civil War, the nation was focused on the transcontinental railroads, while the growth of railroads came slowly in South Carolina.

B. Railroads throughout the United States were built with a standard gauge, or width, except in South Carolina, where varied gauges were used.