The expansion of the rail networks led to

*a growth in the steel industry.

*a growth in the textile industry.

*a decline in the coal industry.

*a decline in the meatpacking industry.

a) A growth in the Steel Industry

Explanation:

Steel had a big impact on the society and was used for railroads rails, train cars, buildings and bridges. This caused the steel industry to grow. Steel shaped American cities and became important to construction.