CS-16 Box Cars:
SA&AP 3146-3245 (to SA&AP 6900-6985)
These 36', 30-ton ventilated box cars were built by AC&F in 1900. They featured 5'-6" side doors, 2'-0"x0'-6" end doors and 1946 ft3 capacity.
For more detailed information, consult Tony Thompson's book Southern Pacific Freight Cars Vol. IV: Box Cars.