| Owner: | Martin Marietta Materials Incorporated |
| Type: | Open Hopper |
| AAR Class: | HMA: (Ore Car) Open top self-clearing car, having fixed sides and ends and bottom consisting of two divided hoppers with doors hinged lengthwise of car and dumping between rails. |
| AAR Type: | K384 |
| Detail Info: | Hopper, Load Limit: 185,000 and greater, Less than 3000 cu ft capacity *Light Density Service |
| Plate: | B |
