What is this? (shuttle related)

OK campers,

What is this . . . the best I could come up with was a mounting point
on the many-tired trailer you occassionally see being used to move
orbiters around. But, why the note indicated which way goes up? I
mean between all the times its been done and the use of in hand
procedures . . . this seems a little silly.

http://upload.wikimedia.org/wikipedi...ting_point.JPG

The winner gets an "I miss Henry (and Rusty, et al) t-shirt.

Take care . . .

John