This standard plan was referred to as the 24' x 64' plan. It contained living quarters for an agent/operator, and it came with two floor plan configurations.
At first glance, this looks quite a bit like the old Bragg City, MO (River Division - Caruthersville Branch) depot. I'll have to confirm, but meanwhile I can't wait to start scratchbuilding. Thanks for posting, Karl. Best Regards,