When the railroad officials found their tracks and roundhouse in the possession of a mob which defied them, they called upon the mayor of the city for protection, to which Mayor McCarthy promptly responded, going in person with a detail of officers to the scene of the trouble. When the police arrived on the ground they found an excited assemblage of people who refused to listen to their orders to disperse, and the mayor made no serious effort to enforce his authority effectually. There was no collision, however, until a man who had refused to join the strikers attempted to couple some cars, when he was assaulted. An officer of the road who undertook to turn a switch, was also assaulted by one of the mob, who was arrested by the police. His comrades began throwing stones, but the police maintained their hold of their prisoner, and conveyed him to the jail. A crowd then gathered in front of the police station and made threats of rescuing their comrade, but no overt act was committed. The mob, which had by this time become greatly enraged, was really not composed of railroad employees, who had contemplated no such result of their strike, and now generally deplored the unfortunate turn which the affair had taken. It was for the most part composed of the worst element of the population, who, without any grievance of their own, real or imagined, had gathered together from the very force of their vicious inclinations and the active hope of plunder. The strikers held a meeting that evening, at which they demanded that the ten per cent. should be restored, and the running of double headers abolished. In the meantime, the railroad authorities, perceiving the inefficiency of the local police powers, and alarmed at the still-increasing mob and the vicious spirit which it displayed, invoked the aid of the sheriff of the county. At midnight Sheriff Fife came to Twenty-eighth Street with a hastily summoned _posse_, a part of which deserted him before he reached the scene of action, and ordered the rioters to disperse, which they, with hoots and jeers, defiantly refused to do. The sheriff then sought aid from the military, and General A. L. Pearson issued an order to the Eighteenth and Nineteenth regiments of the National Guards of Pennsylvania, with headquarters at Pittsburgh, to assemble at half past six the next morning, armed and equipped for duty. Sheriff Fife also telegraphed to the State authorities at Harrisburg, stating that he was unable to quell the riot, and asking that General Pearson be instructed to do this with his force; and Adjutant General Latta issued the orders accordingly. General Pearson marched his forces to the Union Depot and placed them in position in the yard and on the hillside above it. The mob was not, however, deterred by this action, as the troops were supposed to be more or less in sympathy with the strikers, and were expected to be disinclined to fire upon their fellow citizens if they should be ordered to do so.