The 8-1-2 means this car has a 8 seat section, one drawing room and two compartments.
A Section is an open area of the car for daytime travelers and converted at night to upper and lower berths. Not much privacy but you did have a curtain to pull for some sort of privacy.
The Drawing Room was for the elite who paid more. This was basically a private room but most importantly your butt had it's own toilet!
The Compartment was a smaller room than the drawing room but still private with no private toilet!