The correct answer to this open question is the following.
Prior to the Great Depression, basic industries, such as the railroad industry, barely made a profit. The reason why the railroad industry was not as profitable as it had been was that other forms of transportation competed with railroads.
In the 1920s, new forms of transportation were developed due to technological advances and the construction of roads. We are talking about cars produced by Henry Ford and trucks that served to transport goods to different parts of the country. Those were the years of the "Roaring 1920s," were the US economy lived a period of prosperity due to consumerism and the purchase on credit. Everything changed on October 29, 1929, after the US stock market crashed, starting the Great Depression.