Monitoring Rail Corrugation Growth at BART
Bay Area Rapid Transit District (BART)
San Francisco, CA
As most BART patrons are well aware, the system suffers from severe corrugation that can increase noise levels by up to 15 decibels. The noise due to corrugation generates vigorous complaints from communities adjacent to the BART system and causes unacceptably high noise levels inside the vehicles. Currently the only solution to this problem is to grind the rail smooth or replace the rail. But the corrugation often returns within a few months.
The decision of which track segments to grind is commonly based on which communities complain the loudest and the most frequently, but BART management wanted to implement a more scientific approach. That is why ATS was brought onboard.
ATS is implementing a three-pronged approach for addressing the rail corrugation issue:
1) Track the formation and growth of corrugation through system-wide noise measurements inside the vehicles at regular intervals,
2) Perform detailed evaluations of specific problem areas, and
3) Prepare software tools to assist BART track maintenance managers in prioritizing rail grinding efforts.
Using this long-term approach, ATS has tested the effectiveness of rail and wheel dampers at reducing noise levels and begun to quantify how well rail dampers retard the formation of rail corrugation. ATS also arranged for consultants from Advanced Rail Management Corp. (ARM) to work with the BART personnel responsible for rail grinding in order to recommend procedures for improving their productivity and the quality of rail grinding efforts and to provide hands-on training for BART staff responsible for operating the BART rail grinding equipment.
The software tool that ATS developed for BART includes spectrogram displays of noise levels that allow maintenance personnel to visualize a vast quantity of noise data, quickly identify problem areas, and prioritize their rail grinding efforts accordingly. (ATS OnTrack™ for BART pictured left.)
This tool is also valuable when comparing noise measurements performed at different times, such as before and after rail grinding, or right-after and 6 months after grinding, when corrugation may have returned. This software tool manages all the noise data using milepost as the key identifier, which means that other data types (such as rail profiles) could be incorporated into the same data management and display system. Although specifically developed to address needs at BART, the underlying architecture of the software is modular. It would be straightforward to modify this tool to help address noise issues at other transit properties.