The railroad route followed the Oregon, Mormon and California Trails. The new line was added and connected Omaha and Nebraska; followed the Platte River; crossed the Rocky Mountains at South Pass in Wyoming; and through northern Utah and Nevada before crossing the Sierras to Sacramento, California. Additional route connected Denver, Colorado and Salt Lake City, Utah and other cities not directly on the route. The Central Pacific laid 690 miles (1,110 km) of track, starting in Sacramento, and the Union Pacific laid 1,087 miles (1,749 km) of track, starting in Omaha. The two lines connected at Promontory Summit, Utah. (Impact) This route was chosen over the route in the southern part of the country because it was less mountainous.
Some pros of the Erie canal include:
Made harbor most important in America
Allows migration to other places
Inspired a transportation revolution
Cons:
Very expensive, dangerous and ugly work
Did not create a canal revolution that was predicted by Clinton
Isolated the south because now the north could rely on the easier to trade NW
Sorry for the unfinished answer but my class hour is up, I will finish answering your questions tomorrow
