Factual error: So the Civil War ends, and the colonel heads for Texas. It must have taken close to a decade to arrive there, for when he rides into Blackthorne, Texas, he's packing a Model 1873 Colt, and a Model 1873 Winchester.
Factual error: As the colonel and his companions ride out of Blackthorne, Texas, they pass Saguaro cacti, which, oddly enough, only grow in the Sonora Desert, a far distance from Texas.
Factual error: When the rebs seize the train, they release the flatcar and caboose. However, since they are on a grade, the knuckles wouldn't separate without slacking up on the strain, either by backing the loco, or pushing the flatcar uphill.