What sort of ladder is this?

[brettule]

I found this 20130315_085529.jpgold wooden ladder in an old factory which seems to have been once a textiles or sewing mill of some sort, I only say this because of the belt driven timber wheels in the ceiling. You can see the drive and the ladder on the far wall.
20130314_103354.jpg
Anyway, it's a light weight wood, probably pine and the treads are gloriously worn from donkeys years of use, all the screws are old brass flat heads. Two things I wondered about the ladder, what is that bit right at the very top sticking out to the right for? And is it a specific sort of ladder for a specific job (ie a roofers ladder or something) which perhaps just happened to be re-appropriated to this mill?

[Arron]

Could it have been used for maintaining the overhead Powertrain ?

[artme]

Probably made from fine grained Oregon.

[cava]

The cross piece at the top looks like it is for stability similar to what I have seen on old library ladders. Perhaps the LH side was docked off to fit into a particular situation.