Bass left Denton County in the spring of 1877 and traveled to San Antonio. Here many cattlemen were gathered to arrange for the spring cattle drive to the north. Joel Collins, who was planning to drive a herd from Uvalde County to Deadwood, Dakota, hired Bass as a cowboy. After six months on the trail the herd reached Deadwood and was sold and all the cowboys paid off by Mr. Collins. At that period Deadwood was a great, wide open mining town. Adventurers, gamblers, mining and cattlemen all mingled together. Though Joel Collins had bought his cattle on credit and owed the greater part of the money he had received for them to his friends in Texas, he gambled away all the money he had received for the herd. When he sobered up and realized all his money was gone he did not have the moral courage to face his friends and creditors at home. He became desperate, and with a band of his cowboys held up and robbed several stage coaches in the Black Hills. These robberies brought Collins very little booty, but they started Sam Bass on his criminal career. In the fall of 1877, Collins, accompanied by Bass, Jack Davis, Jim Berry, Bill Heffridge, and John Underwood, better known as Old Dad, left Deadwood and drifted down to Ogallala, Nebraska. Here he conceived, planned and carried into execution one of the boldest train robberies that ever occurred in the United States up to that time. When all was ready these six men, heavily armed and masked, held up the Union Pacific train at Big Springs, a small station a few miles beyond Ogallala. The bandits entered the express car and ordered the messenger to open the safe. The latter explained that the through safe had a time lock and could only be opened at the end of the route. One of the robbers then began to beat the messenger over the head with a six-shooter, declaring he would kill him if the safe were not opened. Bass, always of a kindly nature, pleaded with the man to desist, declaring he believed the messenger was telling the truth. Just as the robbers were preparing to leave the car without a cent one of them noticed three stout little boxes piled near the big safe. The curious bandit seized a coal pick and knocked off the lid of the top box. To his great joy and delight he exposed $20,000 in shining gold coin! The three boxes each held a similar amount, all in $20 gold pieces of the mintage of 1877. After looting these boxes the robbers went through the train, and in a systematic manner robbed the passengers of about $5000. By daylight the bandits had hidden their booty and returned to Ogallala. They hung around town several days while railroad officials, United States marshals and sheriffs' parties were scouring the country for the train robbers.