Dennis Storzek <destorzek@...>
The Master Car Builders Association and later ARA and AAR mechanical designations recognized these special purpose cars:
XF was an oversize furniture car
XAF was an Automobile and Furniture car. Remember these codes were adopted ca. 1910 and automobiles had become a major commodity by that time,
FB was a Barrel rack Flat. The dsignation was later reused for a Bulkhead Flat.