Ann Arbor Railroad Company case Learning Objectives 1. Practice how to map and allocate costs into services/products. 2. Practice the concept of relevant cost and apply it to differential analysis in a decision-making context of special order. 3. Practice building different cost configurations for different purposes in Excel. Background Ann Arbor Railroad (AAR) is a railroad company that is partly financed by the US Department of Transportation through its high-speed rail stimulus initiative.