The Union Pacific was one of the earliest 19th-century railroads, meeting the Central Pacific in 1869 at Promontory, Utah, to complete the first transcontinental rail link. It is also one of the last surviving major railroads in the United States, sharing dominance of the western and central sections of the country with BNSF Railway.

The Union Pacific’s first route, the Overland, extended from Omaha, Nebraska, where the railroad is still based, to Ogden, Utah. Along the way, it passed through what we know today as southern Wyoming. By the end of the 19th century, the UP trains that ran through the new state had become favorite targets of outlaws Butch Cassidy, the Sundance Kid, and the rest of the Wild Bunch, whose exploits were famously—if not always accurately—portrayed in a 1969 film starring Paul Newman and Robert Redford.

As the most acquisitive railroad of the 20th century, the Union Pacific gobbled up fallen flag after fallen flag, from the Southern Pacific to the Western Pacific to the MKT, known to railroadiana buffs as the Katy. Yet modelers do not consider those roads part of Union Pacific any more than their former employees do...