"The American Civil War (1861–1865) was followed by a boom in railroad construction. 33,000 miles (53,000 km) of track were laid across the country between 1868 and 1873,[28] with much of the craze in railroad investment being driven by government land grants and subsidies to the railroads.[29] The railroad industry was the largest employer outside of agriculture and involved large amounts of money and risk. A large infusion of cash from speculators caused spectacular growth in the industry and in the construction of docks, factories, and ancillary facilities. Most capital was involved in projects offering no immediate or early returns.[30]"

https://en.wikipedia.org/wiki/Panic_of_1873#Factors

"In the United States, the panic was known as the "Great Depression" until the events of 1929 and the early 1930s set a new standard.[2]"