It always seemed to come down to railroads in the 1800s. Railroads fueled much of the economic growth in the United States at that time, but they required that a great deal of upfront capital be devoted to risky projects. The panics of 1837 and 1857 can both be pinned on railroad investments that went awry, creating enough doubt about the banking system to cause pervasive bank runs. The fatal spark for the Panic of 1873 was also tied to railroad investments—a major bank financing a railroad venture announced that it would suspend withdrawals. As other banks started failing, consumers and businesses pulled back and America entered what is recorded as the country’s longest depression.