Final answer:
Commodore Cornelius Vanderbilt responded to other railroad leaders selling off their shares by buying more shares himself, further consolidating his control over the railroad industry.
Step-by-step explanation:
When the leaders of other railroads were trying to sell off their shares, Commodore Cornelius Vanderbilt chose to buy more shares. Vanderbilt was an insightful leader who made significant industrial contributions to the railroad industry. He was known for his strategic consolidations of smaller railroad lines into the powerful New York Central Railroad Company, enhancing the American economy. This was characterized by his investment in trunk lines that eventually allowed him to connect Chicago to New York City with a comprehensive railroad network, marking a significant expansion of his empire. Through these actions, Vanderbilt became one of the richest Americans of his time, with a massive personal wealth that highlighted the success and impact of his business ventures on the country.