The mansion you are likely referring to is The Breakers, which was the summer home of Cornelius Vanderbilt II. Cornelius Vanderbilt II was the grandson of Cornelius Vanderbilt, a prominent American industrialist and philanthropist. The Vanderbilt family amassed significant wealth through their involvement in industries such as shipping and railroads.

While it was Cornelius Vanderbilt II's grandfather who played a key role in the family's business ventures, including the expansion of the New York Central Railroad, it was his great-grandfather, Cornelius Vanderbilt, who was known for his significant contributions to the development of the railroad industry.

Cornelius Vanderbilt, the great-grandfather, was indeed involved in the railroad business and played a role in the expansion of the Southern Pacific Railroad, among other endeavors. The construction of the railroads in the 19th century often involved the labor of thousands of workers, including Chinese laborers, who were instrumental in building the western portion of the transcontinental railroad.

The connection between the Vanderbilt family's wealth, derived in part from railroad ventures, and the labor of Chinese workers in the construction of railroads is a historical aspect tied to the broader history of industrialization and infrastructure development in the United States. It's worth noting that the labor practices during the construction of the railroads, including the exploitation of Chinese laborers, have been subjects of historical study and discussion.