What was the major contribution of the railroads to the industrialization of the nation?

The boom in railroads contributed to the industrialization
of the nation in some very important ways.  It led to a huge increase in the demand for
steel and it allowed a host of industries to grow which relied on the railroads to get
their raw materials and their finished goods to and from their
factories.

As the railroads boomed, demand for steel
skyrocketed.  Steel was needed for tracks and for rolling stock.  This helped the steel
industry to grow, driving industrialization.  At the same time, the railroads allowed
other industries to grow.  Industries were now able to move huge quantities of raw
materials to factories just about anywhere in the country.  They could then move the
finished goods around the nation equally easily.

In these
ways, the railroads contributed in tremendous ways to the industrializtion of the
US.