Some common sources of rail noise are:
Rail wheel squeal occurs where the curvature of the track and the steering performance of the rail wagon results in a misalignment of the rail and wheel interface. This misalignment produces friction between the metal wheel and rail head, which can result in a high frequency noise or wheel squeal.
What is Pacific National doing about Wheel Squeal noise?
Pacific National has partnered with Transport for NSW (recognised industry leaders in rail freight noise improvement processes) to systematically and scientifically identify the drivers for rail wheel squeal. Through this process the industry has identified that the original manufactured design of the rail wagon bogies (the wheel assembly associated with rail wagons) is critical to preventing the occurrence of wheel squeal. As a consequence, the Assets Standards Authority has issued a new standard commencing the 1st January 2018 which prevents the purchase of new non-confirming bogies and puts in place timeframes for the rectification of existing non-conforming bogies.
Brake Noise is typically the low frequency noise from wagons associated with train braking. The occurrence and level of Brake Noise is influenced by geography and topography, track speeds, track conditions and wheel and brake structure.
What is Pacific National doing about brake noise?
Pacific National is actively involved in collaborative research to systematically and scientifically identify the drivers for brake squeal. To date this research has identified the potential to reduce brake noise through changing the design of brake shoes. Preliminary trials conducted in the Kemira Valley (near Port Kembla) have produced encouraging results. Pacific National will extend this research to further wagon types to validate the effectiveness of this work.
The sounding of the train horn is a critical safety measure to warn people in or near the rail corridor that a train is approaching or about to move. The sound of train horns is distinctive, which is important as it allows the warning to be differentiated from other warning and alert tones that may be used in the same general area. Train horns are required to be sounded at level crossings or when approaching workers or members of the public on or near the track, as well as in emergency situations.
Locomotive idling noise results from a locomotive sitting in one position for a period, where the engine idles. Locomotive idling can occur on the mainline due to network pathing requirements. Idling can also occur at fixed sites such as rail yards, terminals and sidings due to operational requirements.
Bunching and Stretching:
As trains slow down or speed up, the movement of the rail wagons can generate noise. Bunching is caused by wagons bumping together as trains slow or halt. Conversely, stretching occurs as wagons pull apart, typically during acceleration. Topography has a major impact on train bunching and stretching.