Abstract: Under a maximum welfare objective, an urban rail transit system is optimized subject to various financial constraints. For the system, the decision variables including fare, headway, route spacing, and service zone area are optimally solved to analyze unconstrained, break-even and subsidy cases. Numerical results and sensitivity analysis are presented in the paper. From the numerical evaluation, it is shown that the optimal welfare curve is very flat over a wide range of subsidies. Thus, with the welfare maximization objective, the break-even transit subsidy policy may be preferable for the urban rail transit system. The results derived from this study can support effective decision-making on urban rail transit systems in areas that may experience significant shifts in residential density, as well as geographic or physical changes in their street networks.

Key words: engineering of communications and transportation system, maximum welfare, urban rail transit, transportation subsidy