The Monarch Branch, and stock car questions.

I have been doing some studying on tonnage ratings for all of the D&RGW locomotives from Alamosa to Durango. I actually was looking at a timetable from 1951 that showed all of the tonnage ratings from almost every point on the line. My dad pointed out to me that most tonnage ratings aren't based off of what a locomotive is really capable of hauling total, but what it is capable of hauling at a reasonable speed to get over the line on time.
The tonnage ratings for the 490's and the 480's on the Monarch branch were even lower yet than Chama to Cumbres.
What was the grade like up the Monarch Branch? How long was it?
I also have a question about stock cars. I am trying to get a hold of a book on ebay right now on D&RGW narrow gauge rolling stock so I can learn all of the series of cars and lengths and all, my favorites are the 40' reefers. But what types of stock cars were there? I know there were double deck and single deck cars. Were the single deck cars used for cattle primarily? And the double deck cars used for like, well, anything smaller than a cow?
Thanks alot!
Kevin Bush