ATS Consulting, in conjunction with TOADAL.NET, developed CorrTracker® to provide detailed information on track conditions using noise measurements recorded onboard trains. This straightforward and easy-to-implement tool helps transit management maintain their rail transit system and keep it in a state of good repair. It does this by identifying and tracking the formation and growth of corrugation system-wide.
As part of the normal wear and tear of a transit system, this corrugation can increase noise levels by up to 15 decibels. To fix this, maintenance workers must either grind the rail smooth or replace the rail altogether. Before CorrTracker, deciding which track segments to grind relied mostly upon which communities complained the loudest and most frequently. Now, CorrTracker enables transit management to apply a more scientific approach to prioritizing rail grinding efforts and creating work orders.
After a day of riding trains and recording speed, milepost, and noise, ATS can map the noise levels to specific sections of track and provide a rating of track condition for each 100 to 200 ft length of a track.
CorrTracker then shows where the noise levels exceed the average by plotting the noise on satellite photos or by generating tabulated reports. This form of visualization makes it easy to identify locations for grinding and, more importantly, correlate problem areas with existing track features.
Shawn Duenas records noise measurements onboard the train, which he later analyzes and uploads into the CorrTracker online system.
The current ATS CorrTracker system consists of the following components:
1. Field Measurement Equipment
As shown in the above image, the field equipment used to gather noise measurements consists of
A radar gun at the top of the bracket
An instrumentation quality microphone at the bottom of the bracket
A National Instruments 4-channel DAQ for recording the data (not shown)
USB cords to connect to the computer
A laptop computer
A triaxial accelerometer array for measuring ride quality (also not shown)
All equipment is packaged into a roller case about the size of airline carry-on luggage.
The National Instruments system is operated using code developed using National Instruments LabVIEW.
2. Data Analysis System
The field data is post-processed to obtain the spectrum of the sound data at 250 ms intervals into a speed curve that has all glitches from spurious reflections and dropouts removed. To find the milepost for each audio interval, the smoothed speed curve is integrated. The time that the platform ends were passed is used to transform the time vs. distance curve into a time vs. milepost (chainage) curve. The final step is to calculate noise metrics for each track segment. The metrics include maximum and average sound levels over segments of track. The segments can be as short as 100 ft.
The post-processing is performed with customized MATLAB code that has been developed by ATS engineers.
3. Data Storage
The results from the data analysis are uploaded to a SQL server that can be stored on a TOADAL.NET server or transferred on to the customer’s server. The data stored on the server includes the original WAV files and the processed data from step 2.
All of the historical data is retained, allowing for track condition comparisons at a specific location, or over the entire rail system for the full period that CorrTracker has been in use.
4. CorrTracker® Software
CorrTracker, developed by TOADAL.NET, is a web-based tool for displaying all sound measurement results. It can also be used for comparing historical data with current data. The data is stored in SQL tables for fast access. The result is a high-performance application with low wait times to view data in a dynamic fashion.
Some of the current features of CorrTracker include:
Access table views of measurement results
Compare sound levels over time, or over multiple measurements on same date
Allows straightforward access to all measurement data (currently noise measurements)
Displays results in graphic form
Allows playback of recordings to correlate noise with spectral graphs
Uses noise overlays on Google Earth maps to identify exactly where problem spots are
Displays ranked results by segment (station-to-station) in graphic form to help determine grinding priorities and overall health of the rail system
Set way-points on Google Earth maps for grinding work orders
CorrTracker is registered to CorrTracker LLC, owned by ATS Consulting and TOADAL.NET.
To learn more about CorrTracker, contact ATS today!