Even loose loads such as coal, grain and ore can be carried in a boxcar with boards over the side door openings. Later grain transport would use metal reinforced cardboard which was nailed over the door and could be punctured by a grain auger for unloading. This was more common in earlier days; it was susceptible to losing much loading during the journey, and damaged the boxcar. It was also impossible to mechanically load and unload. Grain can also be transported in boxcars designed specifically for that purpose; specialized equipment and procedures are required to load and unload the cars. However, the grain is better transported in covered hopper cars.