What is this piece of equipment?

What is this piece of equipment?

I found this pic at:

http://www.railpictures.net/viewphoto.php?id=132091

Can you please tell me what the piece of equipment is on the left, it appears that it is numbered as "962" Norfork and Southern.

Please excuse my ignorance, I am just starting on trying to get into railroading.

Thanks in advance, stay safe.

Its a yard slug, it is a unpowered locomotive frame powered from rhe mother unit.
Their used to spread pulling power over more wheels and tractionmotors for low speed in hump yards etc.

To elaborate on DutchRailnut's explanation:

Basically they took a locomotive, removed the engine and the cab, lowered the hood, and modified it so that its traction motors receive electricity from the "real" locomotive it is coupled to.

Sometimes they leave the cab and operator controls in place; those units are known as "road slugs" and can be used on the head end of the train. They are nice from the crew's point of view because they're so quiet.