Urbanization has altered the daily demand of transportation. Ridership of public transit has increased by 30% since 1995 and in 2013 more Americans used trains, subways and buses than ever before totaling 10.65 billion trips. These trips, according to the American Public Transportation Association (APTA) , help avoid the use of 4.2 billion gallons of gas annually throughout the country. Although rail systems themselves require a considerable amount of energy to operate, they still provide a great benefit to communities and the environment.
In continuing efforts to further reduce the amount of energy needed to operate their trains, stations, and tunnels, subway operators have turned to innovative solutions to help increase their bottom line. Many of these energy-efficient features focus on the passenger experience; self-starting escalators, natural light and air ventilation. However as the grid becomes less reliable , more attention is being focused on improvements to the rail infrastructure itself.
A Rail System Overhaul Needed
Rail-based networks support just over a third of all trips (35%) yet have the greatest maintenance needs compared to other transit modes, with a backlog of $59 billion as compared with $18 billion for non-rail systems. In addition, these systems experience the most wear and in turn have larger than average annual replacement needs. This presents a serious financial test for governments dealing with their transit budgets, notably for cities like New York, Boston and Chicago who deal with some of the country’s oldest infrastructure assets.
Just as troubling as the maintenance backlog is the fact that many transit agencies do not systematically monitor the conditions of their facilities to keep their fleets in clean and consistent operation. Lacking regular comprehensive asset condition assessments, rail engineers find themselves falling behind other transportation sectors, often lacking the information other departments maintain in order to determine inefficiencies.
Struggling in the Heat
Things aren’t getting easier for the already problematic rail-systems. As major cities continue to add more layers and pack in more residents, their corresponding grids are being pushed to new limits. In the summers especially, high A/C use during the day drives voltage demand very high, often beyond designated standardized voltage levels. In these instances, rail-systems are forced to enable their uninterruptible power supply (UPS) units to ensure reliable service is maintained throughout such stressed electrical conditions. At night however, voltage levels increase with the lack of demand causing a UPS to remain operational, heavily taxing the systems’ expensive batteries while correcting for an over voltage condition. The inability of a UPS to accommodate routine voltage spikes results in battery replacement too often and jeopardizes engineers’ efforts to maintain cost effectiveness as their systems incur unprecedented demand.
Utilizing Efficient Alternatives
UPS systems are not proper voltage regulators. As rail engineers learn this the hard way, alternative technologies are being put to use throughout the industry to ensure electricity costs remain low and batteries subsist to reach optimal life expectancy.
Amtrak of the tri-state area for example, was experiencing unacceptable wear to their batteries and has since worked with Utilities Systems Technologies (UST) to create a custom solution to their problem. UST’s SureVolt™ Electronic Voltage Regulator (EVR) has been identified as a solution to ensure the UPS and its corresponding batteries were only activated when necessary (typically only for an outage). The Washington Metropolitan Area Transit Authority also sought out UST’s advanced technologies, choosing to employ a series EVRs in a recent electrical upgrade of their system.
While the growth of public transit systems remains inevitable, the cost of operating consistent service shows no sign subsiding. In order for transit agencies to effectively manage complex systems and growing ridership, asset management practices will be essential and usage of the most efficient, innovative and clean technologies will be a requirement.