Why were railroad companies in a hurry to complete many miles of track-laying in the mid 1800s?

They were given many acres of government-owned land for every mile created.

Explanation:

Congress passed the Pacific Railroad Act in 1862. This led to the creation of the Union Pacific and the Central Pacific.

a big wall across the mexican border so no drugs, terrorist, or illegal immigrants can come through : )    

c. troops marched forward in close formation against newer, more accurate weapons