The building of a railroad network led to industrial growth because

The building of the railroad network in the US, led to industrial growth because it made possible for goods and materials to be transported rapidly through the network, this made the transportation cheaper and faster which made possible for industries to produce more goods with less money. This led to a transformation in the entire industry because people were able to produce more, sell more and economy developed with the creation of new cities close to the railroads and the new jobs they brought with them.

Raw materials and finished products were shipped quickly and cheaply.

This made it made more jobs since the products and materials were arriving faster than ever before.