Because of the competition with cars, trucks, and buses, railroads became less used.

Steel, though used in automobiles, experienced a decline in industry because of the downtrend in railroads.

Railroads

Steel

Automobiles

Agriculture

Failing Industries

There was a huge boom in the automobile industry that stopped when overproduction occurred.

Overproduction, due to advances in technology, led to prices dropping and a falling demand for crops.