Principal Investigator/Researcher
Dr. Mehdi Ahmadian, Virginia Tech
Project Description
The primary objective of this research is to design and develop a practical energy harvester tie (EHT) that can be used for setting up remote electric power stations to satisfy the needs of the railroad industry. The need for power in remote places often arises from the implementation of sensors or other devices that require DC power. The lack of the availability of power has been limiting the implementation of smart technologies on railroad tracks that can bring much operational efficiency and cost savings. This project will design and develop an EHT that can be used for providing power to track mounted systems or through a wireless charging station for devices that are not track mounted. One such application is drones that are often railroads desire to operate, but their applications are limited with the limited flying range. The remote station that is possible to set up through the implementation of EHT promises to not only make it possible to install smart systems on the rail but also significantly increase the operational viability of critical technologies such as drones.
This study evaluates a compact electromagnetic energy harvester that can be installed at the railroad tracks. The design integrates a mechanical motion rectifier (MMR) with an embedded one-way clutch in the bevel gears, to convert the movement that commonly exists at the track due to passing train wheels into a unidirectional rotation of the generator. The ball screw mechanism is configured such that it has reduced backlash and thus can more efficiently harvest energy from low-amplitude vibrations.
A porotype energy harvester tie will be designed, fabricated, and tested expensively in the field. The design will include the integration of a proven energy harvester concept into a composite railroad tie that is suitable as a direct retrofit with a conventional railroad tie. The intergradation into a conventional railroad tie provides ease of field installation and improved the efficiency in harvesting the mechanical energy at the rail. The integrated design, referred to as the “smart tie,” not only protects the energy harvester, the wiring harness, and supporting electronics from the maintenance-of-the-way equipment but also positions the harvester in a mechanically advantageous position that can maximize the track-induced motion, and hence the harvested power. Although for testing purposes, the smart tie uses a modified composite tie, it can be integrated into other track tie arrangements that used for revenue service track, including concrete and wooden ties.
Implementation of Research Outcomes
The technologies related to determining the early stages of ballast fouling are currently under development as part of our efforts. The next step in our development is field testing of the approaches and technologies that are being evaluated. Once they are proven, we intend to pursue implementation as a pilot program, in collaboration with industrial partners.
Impacts/Benefits of Implementation
There exist no proven methods for harvesting energy from the track. The current means of providing trackside power is limited to solar panels or propane-operated generators. Solar panels are subject to vandalisms and theft. Additionally, their power output is limited or nonexistent on cloudy days and at night. Propane-operated generators require frequent filling and service. The Smart Tie will eliminate both of these shortcomings and provide the means for integrating sensors and monitoring devices into the rail. This would significantly improve the diagnostics and prognostics of track maintenance, potentially yielding significant cost savings and improved safety for the U.S. railroads.
Web Links
General Approach for the Proposed Research
Laboratory test setup for ½-tie Energy Harvester Tie (EHT) prototype