Minimum Cost Locations for Parallel Public Transit Lines

Passengers are to be carried to a rapid transit line by feeder transit lines perpendicular to the rapid transit line. How should the feeder lines be located and how should their schedules respond to a passenger arrival pattern that varies with location and time? These questions are answered for a system with a simple cost structure by using continuous functions to approximate the behavior of the system, then minimizing the cost by the methods of elementary calculus.