How did the transcontinental railroad transform the west?

(I know this is alot but if you read this you will understand everything about what you are asking)
When finished, the Transcontinental Railroad spanned the vast territory between California and the Missouri River, cutting the travel time through this region down to six days rather than four to six months. 
With such an increase in the speed of travel, the states became more united and the world felt smaller. 
The telegraph lines that were strung up alongside the railroad added to this feeling by enabling nearly instantaneous communication across the country. 
Obviously, this new capacity for travel and communication had significant impact. 

Enhanced transportation allowed for increased commerce between the states. 
Fifty million dollars worth of cargo annually surged across the railroad during its first decade of use. 
Asian goods and raw materials flowed out of the West, and a stream of finished products issued from the East. 

This trade sparked a manufacturing boom in the recently industrialized East by keeping it supplied with minerals mined in the western regions. 
Additionally, the West began to catch up with the Eastern way of life as the products of the manufacturing boom flowed to the frontier. 
Ultimately, the trade induced by the Transcontinental Railroad accelerated the progress of the entire country. 

One of the evidences of progress in the West was rapid settlement. 
In fact, the settlement of the West may have been the single most important effect of the Transcontinental Railroad. 
After the railroad's construction, traveling became much simpler, and families flocked west. 
Cheap land attracted settlement as the railroad companies sold their grant-lands and the federal government offered other land (called homestead land) to settlers for free. 
Soon new railways branched off of the Transcontinental Railroad, and others ran parallel to it, creating a network of tracks that transformed the West from an unpopulated wilderness to a thriving region of mining and agriculture. 

Hope this helped you,

Melanie :)