Noise Monitoring
Synopsis
Specific locations on the client's tram network were prone to wheel squeal. The client was aware that existing lubricators were not providing sufficient lubrication to prevent squeal. The maintenance cost for the current lubrication system had also been identified as an issue, and the noise was also a concern to local residents.
The client needed to ensure that sufficient lubrication would be provided at each location, for the lowest lifecycle cost, and prevent excessive rail/wheel wear as well as reduce noise to an acceptable level.
Key Client Issues
Key sites on the tramway system were affected by squeal, giving rise to noise complaints from local residents. This was thought to be due to insufficient lubricant being delivered by pre-existing lubricators. The client was also incurring a perceived high monthly cost for consumables. Tata Steel was asked to investigate the noise problem and alternative lubrication systems. The client required:
- A trial for alternative lubrication with the aim of reducing noise levels.
- An effective solution for track lubrication across the network.
Solutions
Tata Steel conducted a survey to identify the extent and causes of wheel squeal. This included:
- Managing a trial with a modified rail lubricator.
- Noise monitoring specified locations.
- A literature review of wheel squeal and the types of lubrication and methods of application available.
- Investigating the effect of wheel profile and wheel-rail contact path on wheel squeal.
Noise measurements obtained pre-lubrication indicated that squeal was caused by the wheel-rail interaction, which was causing the wheel to vibrate to its resonant frequencies, generating the maximum measured noise level. Squeal also varied from vehicle to vehicle. The key factors affecting noise levels were identified as:
- Tram speed at noise monitoring locations.
- Tram wheel diameter/profile.
- The performance of the wheel flange lubrication system on each tram.
Client Benefits
Our report enabled the client to:
- Have comparative data for squeal from different trams.
- Implement a new lubrication system and remedy rail and wheel issues.
- Reduce noise levels in problem areas.
