A Typical Requirement

Our requirement is as follows:

I have finished product storage location

I have rail cars (container) for packing the finished product

I will use rail cars as for storage also

I will store the Finished product in rail cars(with our any sales order or delivery)

as and when I get requirement from the client ( Purchase order) I will create sales order and assign the rail car with finished product in delivery with ref to sales order

I should know what is my stock in storage location

I should know the stock available in the rail cars in my plant

I should know the stock in total (storage location+rail cars)

I should know the stock of empty rail cars in the plant

I should know the stock of rail cars of ours with the customer

when my rail car is filled with finished product with its full capacity , I should not able to transfer the finished product in that rail car which is already full in capacity.

How can i execute in SAP SD.