The answer is: The Great Railroad Strike of 1877 was the first major strike in an industry that propelled America's industrial revolution. It was the first national strike.
The great railroad strike was done mostly by employees of railroad companies who treated their employees unfairly.
At that time, the railroad companies keep cutting the wages of their workers and icnreasing their working hours to increase the company's profit. The strike got more attention that the companies tought it would.
In the end, the companies that became the target of the strike cave in and improve the workers' salary with additional medical benefit.