ABSTRACT
The cost of adding a bus, an additional car to a train, or an entire additional train into service is an important consideration in many planning and operations analyses. This chapter first describes basic concepts and gives a few examples of how marginal costs might be used. It then derives marginal-cost formulas based on the average annualized cost equations described in Chapter 9. It continues by using both the average and marginal-cost equations in examples. This chapter then develops a methodology for estimating operating costs for entire bus routes and rail lines. It concludes by addressing two other important questions: How much does it cost to accommodate linked trips (i.e. trips involving connections)? Do particular trips improve or detract from financial performance of a transit network?
