WITH A LITTLE HELP FROM MY FRIENDS (Joe Cocker)

Hi, railfanning people.
I'm italian and I know very few about the north-american locos so I need an explanation.
In a park of Lima (Peru) is plinthed this 3 ft loco, built by Baldwin in 1929 and coming from the Cuzco-Macchu Pichu-Quillabamba line; the loco has two sandboxes and from the far one, and only from that one, comes out a a handy lever control.
Neither me nor my european friends can understand what is this nor why it is only on the second sandbox.
Can anyone explain the mistery?
Thanks in advance and if you need informations about european railways contact me. Ciao

It is hard to tell from the picture, but it appears to be a control valve which has had its control rod accessible in the cab removed for some reason.

Two sandboxes makes operating in both directions easier, as sand can always be put in front of the drivers. As such, only one sand box would need to be used at a time. I suspect the control for the other box is in the cab somewhere.

BTW, awesome song .

Thanks, you're always a certainty, my friend.
How means BTW?

Ciao

It means "by the way".
Thanks, and I hope I have helped!