How did the railroad affect the economy of the West?

Without the railroads, the economy of the West would have had a very hard time expanding.

The economy of the West was based largely on mining and agriculture.  Both of these industries needed a way to get their products back to the East, where the vast majority of Americans lived.  If it had not been for the railroads, miners and farmers/ranchers would not have been able to get their products to market.  A perfect example of this would be the famous cattle drives of the Old West.  Cattle were driven from ranches to the railheads so they could be shipped back to the East.

Because of these things, you can say that railroads allowed the West's economy to grow much faster than it otherwise would have.