Although current and new at grade rail systems are upgraded and modernized, their basic design as electrically powered, steel wheeled vehicles on traditional steel rails limits their adaptability and potential for significant change in energy consumption, performance or durability. Limits of the sustainability of passenger services on this type of systems tend to be defined by the consumption and cost of electrical power, fare income levels and the ability of maintenance personnel to keep the equipment in service. While equipment is most likely to fail or ware out, the costs, and revenues required to maintain electrical power distribution systems and optimal repair status of system components is a key factor in the sustainability of reliable, high quality and performance of passenger services.
Long term financing, debt service and funding priorities tend to set the limits and sustainability of transportation services. The point at which services substantially fall below performance and funding minimum thresholds should cause an evaluation of the sustainability of continued service under existing conditions. Sources and costs of electrical power required to operate rail systems may be brought under pressure by the consistent and significant demands of equipment and systems operations. Public utilities’ efforts to conserve or reduce electrical power generation are not likely to receive any relief from at grade rail systems’ power consumption and demand.
No at grade rail mass transit system has proven to be sustainable based on its own ridership revenue. All such systems have been, and continue to be heavily subsidized by governmental appropriations of public funds and tax revenue. Most people accept that they should pay for transit service, but many object to subsidizing programs and services that they do not use or depend on. When fares are maintained at artificially low levels, transit services are perpetually subsidized by other sources of funding. Set at appropriate fare levels, the relative costs and efficiency of the various technologies used in mass transit would clearly reveal that at grade rail is one of the most expensive, and least cost-effective transportation technologies in use today.