Railroad companies spend billions of dollars each year to purchase fuel for thousands of locomotives across the railroad network. Each fuel station charges a site-dependent fuel price, and the railroad companies must pay an additional flat contracting fee in order to use it. This paper presents...

A methodological framework is formulated so that continuum approximation techniques can be used to design bus networks for cities where travel demand varies gradually over space. The bus-route configurations that result consist of (i) a main, possibly city-wide grid with relatively large...