Small yellow tags on auto racks

While train watching recently near the Ford truck plant in St. Paul, MN I noticed that most of the auto racks have small, 3 or 4 inch long yellow, triangular tube shaped tabs more or less centered over each truck at about eye level. They appear to have black printing on them though you would have to be fairly close to the car to read them. Does anyone out there know what these are? Thanks.

Havn’t paid much attention while switching autos, could be bad order card holders. I’ll take a look next time I switch em.

The thing is part of the door locking mechanism. The writing on says “The Grate Lock Chock”. It holds the door open for unloading.