The original emigrant route across Wyoming of the Oregon, Mormon and California Trails, after progressing up the Platte River valley, went up the North Platte River valley through Casper, Wyoming, along the Sweetwater River and over the Continental Divide at the South Pass. The original westward travelers in their ox and mule pulled wagons tried to stick to river valleys to avoid as much road building as possible—gradients and sharp corners were usually of little or no concern to them. The ox and mule pulled wagons were the original off-road vehicles in their day since nearly all of the Emigrant Trails went cross country over rough, unimproved trails. The route over South Pass's main advantage for wagons pulled by oxen or mules was a shorter elevation over an "easy" pass to cross and its "easy" connection to nearby river valleys on both sides of the continental divide for water and grass. The emigrant trails were closed in winter. The North Platte–South Pass route was far less beneficial for a railroad, as it was about longer and much more expensive to construct up the narrow, steep and rocky canyons of the North Platte. The route along the North Platte was also further from Denver, Colorado, and went across difficult terrain, while a railroad connection to that City was already being planned for and surveyed.
The original emigrant route across Wyoming of the Oregon, Mormon and California Trails, after progressing up !the Platte River valley, went up the North Platte River valley through Casper, Wyoming, along the Sweetwater River and over the Continental Divide at the South Pass. The original westward travelers in their ox and mule pulled wagons tried to stick to river valleys to avoid as much road building as possible—gradients and sharp corners were usually of little or no concern to them. The ox and mule pulled wagons were the original off-road vehicles in their day since nearly all of the Emigrant Trails went cross country over rough, unimproved trails. The route over South Pass's main advantage for wagons pul?led by oxen or mules was a shorter elevation over an "easy" pass to cross and its "easy" connection to nearby river valleys on both sides of the continental divide for water and grass. The emigrant trails were closed in winter. The North Platte–South Pass route was far less beneficial for a railroad, as it was about longer and much more expensive to construct up the narrow, steep and rocky canyons of the North Platte. The route along the North Platte was also further from Denver, Colorado, and went across difficult terrain, while a railroad connection to that City was already being planned for and surveyed.