Hopper car contents Crossword Clue

 The answer to the crossword clue "Hopper car contents" is GRAINS.

A hopper car is a type of railroad car that is used to transport loose bulk materials, such as grain, coal, and sand. The car has a large hopper at the bottom that is open at the top. The material is loaded into the hopper through a hatch in the roof.

Grains are a major type of cargo that is transported by hopper car. Other common cargoes include coal, sand, gravel, and cement.

Here are some other possible answers to the clue, depending on the specific crossword puzzle:

COAL

SAND

GRAVEL

CEMENT

PETROLEUM

I hope this helps!