Building through the Sierra Nevada Mountains was very difficult and dangerous. Temperatures were freezing during the winter and in one year alone there were 44 storms.There was the great danger of an avalanche for the men working through 18 feet of snow and camping on the tunnels beneath it. Creating tunnels through the mountains required blasting with nitroglycerin. Advancing at one foot of mountain at a time, a total of 11 tunnels was created.
Answer:
My best guess would have to be trees.
Explanation:
I cannot think of the correct term off the top of my head, but in this region (the Middle East,) there are many trees and forests.
National Grange of the Order of patrons of Husbandry
Advances in steel production and oil refining affect US industry History greatly in that it led the US to be one of the more leaders of the Industrial Revolution, next to Britain.