| FM | Ordinary flat car for general service. Has flooring laid over sills and without sides or ends |
|---|---|
| FC | Flat car equipped to carry Trucks or Trailers for transportation of freight. |
| FD | Flat car of special construction having the portion of the floor between the trucks depressed to provide necessary headroom for certain classes of lading. |
| FG | Flat or gun truck car for special transportation of heavy ordnance or other heavy commodities. |
| FW | Flat well hole car for special transportation of plate glass, etc. Flat car with a hole in the middle allowing lading to be dropped down on account of clearance problems. |
| FB | Flat car having skeleton superstructure, suitable for carrying barrels, known as a "Barrel Rack Car". |
| FL | Flat Logging car or logging truck.An ordinary flat car or car consisting of two trucks fitted with cross supports over truck bolsters; the skeleton connected by a skeleton of flexible frame and logs loaded lengthwise on cross supports. |
| LF | Flat car equipped with one or more demountable containers for the transportation of liquids or other commodities not under refrigeration. |
| LFA | Flat car equipped with a container or containers for the purpose of transporting commodities immersed in liquids or gases. |
| LP | Open top car having solid bottom and fixed ends (either slatted or solid) , without running boards having guard rails. Suitable for handling pulpwood. |