Question

What was the connection between the Gadsden Purchase and the Southern railroad route?

Answer 1

The Gadsden Purchase was a transaction that followed the conquest of much of northern Mexico by the United States. Its relationship to the transcontinental railroad is that  it was purchased because it was the most practical route  for the transcontinental railroad.  The purchase was negotiated by the U.S. minister to Mexico, James Gadsden.

Answer 2

In 1854, The Gadsden Purchase was made and the first draft was signed by James Gadsden.

It was an agreement between The Unites States and Mexico where The US purchased a 29,670-square-mile  region of present day southern Arizona and southwestern New Mexico.

Gadsden wanted to connect all the southern railroads into one section as he felt that the Southern part was suffering due to the increase of railroad construction in the North and this was bypassing all the trading, farming and manufacturing businesses from the South.