The CP Sudbury Division employs carcards and 4-cycle waybills for the movement of freight cars. This simulates customer demand on a model railway, and helps determine which specific cars will go to which particular industries on your layout.
From left-to-right; carcard for CP 55172, a boxcar from our ‘Pool 101’ (40ft boxcar with 8ft doors), then the front & back of an associated ‘101’ waybill (this example shows a car going end-to-end over our layout in thru-transcon service over all 4 cycles). On the right is a carcard for CP 55269 filled with a waybill, and is what our train crews will see when flipping though their waybill orders.
You can read more about carcard & waybill operations here: https://vanderheide.ca/blog/2017/12/28/simulating-customer-demand-on-a-model-railroad/