The Strategic Business Plan specified route changes that Amtrak was committed to do by the year 2002. By using FY 2002 as the reference year, the MBNA can weigh the expected results of a proposal in the network that Amtrak is already committed to implementing. Changes in the network are reflected as changes in key operating statistics. These operating statistics are used because, based on statistical techniques such as regression, changes in these statistics are the best predictor for how costs will change. The cost model combines a train's operating statistics with the cost of the associated operation.
Variable costs are relatively easy to link with a train's operations.
Fuel cost, labor costs and track access fees all increase with additional frequencies or service to new destinations. Because the focus of the MBNA is to assess the incremental benefit associated with reconfiguring the network or changing how the trains are operated, these operating statistics become the key variables for estimating the incremental change in costs associated with a proposed change of service. Fixed costs are more difficult to attribute to a particular route. For example, the cost of operating the overhaul facilities is not easily allocated to particular routes. To the degree possible, however, overhead and costs that increase in a step-like manner were allocated to their appropriate routes.