How did railroad expansion lead to industrial growth.

Advances in transportation that improved infrastructure and distribution during this Industrial Revolution. Steel and gasoline made a contribution to raw material and fuel. Steel was used to build almost 200,000 miles of railroads in just 40 years, build larger ships and more affordable automobiles. Inventions in the railroad industry included air brakes, Pullman cars, and the standard gauge improved railway transportation. Air brakes provided safety, Pullman cars provided passenger travel rather than just freight travel, and the standard gauge allowed trains to travel on any track. The shipping industry benefited from larger ships, because the ships allowed larger and faster imports and exports. Finally, the automobile industry was improved dramatically by the implementation of assembly lines, which mass-produced cars at quicker speeds and lower costs, allowing cars to be more affordable. As more forms of transportation were provided, more infrastructure such as railroads, ports, and roads were built to support this increased use.  Improved infrastructure and distribution from advances in transportation established a stable American economy.hope this helps

Answer is mass marketing.