Jesus Carranza and Pablo Gonzalez were left in charge at Ciudad Porfirio Diaz by Venustiano Carranza when he left on his trip. Shortly after this a Federal column was organized under General Maas for the capture of the railroad between Saltillo and Ciudad Porfirio Diaz. This column slowly worked its way to Monclova and then to Ciudad Porfirio Diaz, which it occupied on October 7th; the Constitutionalists ripped up the railroad and destroyed everything that might be useful to the Federals and a good deal that could not, and offered very little resistance. Villa, in the mean time, having been reenforced by men from Durango and some from Sonora, had been operating in Chihuahua with considerable success. He had fallen on several small Federal columns, destroyed them, and obtained about six pieces of artillery, besides a fresh supply of rifles and ammunition. In September, he had interposed his force between the Federals at Chihuahua City and Torreon, at a place called Santa Rosalía. Villa and the Federals each had about four thousand men. The Federals from the south were making a determined attempt to retake Durango and had started two columns for Torreon of more than two thousand men each, one west from Saltillo, another north from Zacatecas. These had to repair the railroad as they went. Torreon was being held by about one thousand Federal soldiers. Villa was well informed of these movements, and also of the fact that, in their anxiety to take Durango, a Federal force of about 800 men, under General Alvirez, was to leave Torreon before the arrival of the Saltillo and Zacatecas columns. Having the inner line, Villa with his mobile force could maneuver freely against any one of these. He accordingly left a rear guard in front of the Federals at Santa Rosalía, and, marching south rapidly, met and completely defeated General Alvirez's Federal column about eighteen miles west of Torreon, near the town of Aviles. General Alvirez and 287 of his men were killed, fighting to the last.