FA – Flat car specifically equipped with superstructure or containers for transporting set-up vehicles, not suitable for miscellaneous commodities.
FB – Bulkhead flat cars. Equipped with fixed or permanently attached movable bulkheads or ends a minimum of three feet in height and flat floor for general commodity loading.
FBC – Flat car constructed with a center beam above the car deck from bulkhead to bulkhead.
FC – Flat cars specifically equipped to carry trucks, trailers, containers, chassis, or removable trailer bodies for the transportation of freight in
FCA – Flat car, articulated multi-unit, specially equipped to carry trailers, containers, chassis, or removable trailer bodies for the transportation of freight in TOFC/COFC service.
FD – Depressed-center flat car of special construction having the portion of the floor extending between trucks depressed to provide necessary head room for certain commodities.
FL – Flat logging car or logging truck. This is either a straight-deck flat car, with or without bulkheads or load restraining devices, or car consisting of two trucks fitted with cross supports over truck bolsters; the trucks connected by a skeleton or flexible frame and logs loaded lengthwise on cross supports.
FM – Ordinary flat car for general service. This car has flooring laid over sills and without sides or ends.
FW – Flat car with hole to enable lading to be lowered due to clearance limits.