From 1865 until shortly after 1900, train robbery was an American institution. During the post Civil War crime wave, train robbery enjoyed a certain level of tolerance. Cold blooded assassins, like the James brothers were romanticized in magazines and penny novels. There is an abundance of primary source materials about the murder and mayhem in the wild west, Police reports, court records, lists of criminals that were hanged. Writers for lurid dime novels would embellish these stories and fictionalize them to some extent.
After 1870, the Pinkerton detective agency began to assist local authorities in combating train robbery. West of the Mississippi, it was Wells Fargo that was a large bank, a detective agency and provided armed guards to escort rail shipments of gold and other valuables. Wells Fargo had lent the Big Four, who owned the Central Pacific and Southern Pacific railroads so much money, it was in their best interest to remove anything that would interfere with the smooth operation of that railroad.
The first really large gang of train robbers were the Reno brothers. They operated in western Ohio and eastern Indiana, but in 1868, all ten were caught and hanged. The three Reno brothers were tried and found guilty in New Albany Indiana before they were strung up.
One of Edison's first films was "The Great Train Robbery" It told a story that was firmly established in the national literature of fiction. Jesse James was so popular, a magazine "True Jesse James Stories" was a weekly dealing with the detection of crime. It sold for five cents and was the height of entertainment in an era before movies or radio.
Source " Hear the Train Blow" by Lucius Beebe and Charles Clegg. 1952.