Texas-born outlaw, Tom "Black Jack" Ketchum, enjoyed a colorful career in the 1890s Southwest plundering trains, killing folk and other distinctively American pastimes until August 16, 1899, when he decided to rob a train by himself. He wasn't aware that his brother, Sam and a gang attempted to rob the same train (Atchison, Topeka & Santa Fe), in the same place, five days earlier when Sam was killed.

As Tom was riding toward the train, the conductor recognized him, ran to get his shotgun, got the drop on Ketchum and shot, knocking Tom off the train. He was too weakened by his injury to run so he was caught by a posse the following day. Badly wounded, Tom was taken to a doctor in Trinidad, Colorado, where his right arm was amputated. After recovering, Tom was taken to Clayton, NM Territory, for trial.

The inexperience of the Clayton officials, never having conducted a hanging and not knowing exactly what to do, created a complication. When Ketchum dropped through the trap, he was instantly decapitated. The severed head went rolling and blood was spurting from his neck. Contributing factors were: rope too long, noose too loose and Tom had gained too much weight while in jail. Consequently, Tom's head was sewn back onto his body and he was buried at Clayton’s Boot Hill, NM Territory.

Ketchum was the only person executed for “felonious assault upon a railway train”. Train robbery wasn't a Federal offense unless the robbers stole U.S. mail, which most did.

More Info: en.wikipedia.org