Final answer:
The Federal troops were called in to stop the Pullman strike because it escalated to a nationwide work stoppage disturbing the operation of railways and delivery of mail, a federal offense. The troops' intervention helped quash the labor unrest and restore the normal operation of trains.
Step-by-step explanation:
The Federal troops were called in to stop the Pullman strike of 1894 due to multiple reasons. Company owner George Pullman made severe cuts in employees and their wages at a time of depression, while maintaining high rents and prices in the company town of Pullman, where the workers were compelled to live and shop. This sparked a large scale nationwide strike led by Eugene V. Debs, president of the American Railway Union. To validate the intervention of federal troops, President Grover Cleveland used the strategy of attaching a mail car to every train, thus making the strike hinder the delivery of U.S. mail, which is a federal offense.
When Debs and his men refused to end the strike, he was arrested, and the troops ensured the operation of trains and the recruitment of new workers, essentially negating the effectiveness of the strike. Thus, the Federal troops were called in not just to ensure the operation of the railway and mail system, but also to quash the large scale, nationwide labor unrest.
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