What does D/F stand for? What is the difference between AAR's XL & XML?

I have seen box cars with loading restraining equipment advertising that fact with markings such as “D/F” or “Lading DF2 Loader” or “Cushion Ride.” What does the DF stand for?

On one car that had a large D/F marking on the car side, it had a small XL marking near the door. Do the AAR mechanical designations of XL and XML mean the same thing, namely a box car that is equipped with a loader? Is it simply the time period that would dictate if the box car is classified as XL or XML?

The entries that I have are:

XL” – Loader Equipped. A house car similar in design to “XM”, either fully or partially lined with steel perforated side walls or equipped with interior side rails or stanchions and crossbar members, for securement of certain types of lading and/or permanently attached movable bulkheads (1/68).
Cars equipped with interior side rails only, built new, rebuilt or reclassified on or after January 1, 1966, in order to qualify for the “XL” designation, shall have a minimum of four (4) usable side rails on each wall of car, each extending from doorway to approximately four (4) feet from end of car, plus facilities in doorway to accommodate doorway members. The facilities in the doorway are not required in cars equipped with plug type doors. (1/68).

XL” – Loader Equipped Box Car. Similar in design to “XM”, with steel perforated side walls or equipped with interior side rails for securement of certain types of lading and/or permanently attached movable bulkheads (1/73-1/95).
Cars equipped with interior side rails only, built new, rebuilt or reclassified on or after January 1, 1966, in order to qualify for the “XL” designation, shall have a minimum of four (4) usable side rails on each wall of car, each extending from doorway to approximately four (4) feet from end of car, plus facilities in doorway to accommodate doorway members. The facilities in the doorway are not required in cars equipped with plug type doors (1/73-1/95).

DF = Damage Free

Virlon

Save your ticket… the P.E. will rise again.

XML became XL in the late 1960s. That 1/68 “XL” definition you quote has to be pretty close to the changeover date.

DF (for “Damage Free”) was a proprietary name for the Evans Products Company’s lading protection equipment. It was supplanted by the DF2 loader–a slightly different design. There were other load-restraints built by other companies, but none matched the popularity of the DF and DF2 loading devices.