Examples from literature

• Bunny and Sue crossed the street and walked along the string of boxcars, looking into those the doors of which were open. 
• Is that freight? asked Sue, pointing to some broken boxes on the ground near a boxcar, the door of which stood open. 
• Now he hurried to pass down the train to a boxcar with an open door. 
• One day all of us who were able to walk were made to fall in and march over to the railroad, where we were loaded into boxcars. 
• Rip had never seen an old-type railroad, or he might have likened the landing boat to a railroad boxcar.