The Butler project is a 7.5km extension of the Joondalup rail line to Butler Station situated in the outer Northwest region of Perth, Western Australia

Client: Public Transport Authority (PTA) – Perth
Contractor: John Holland Rail (JHR)
Supplier of the Sub-Ballast Mat: Projex Group Pty Ltd

The PTA required a system that had the ability to extend the life of the ballast and reduce the noise and vibrations from train operations. The vibration control was primarily to protect the adjacent structures and buildings where passenger trains (max 19 tonne axle load) travel through.

Workers installing 20mm SBM

Workers installing 20mm SBM

Projex SBM tape over joints

Projex SBM tape over joints

Geotextile over 20mm SBM

Geotextile over 20mm SBM

If uncontrolled the vibration emissions could flow through the ground to the nearby houses located at the top of the cutting, causing potential environmental (noise) and structural (vibration) issues.

The solution was to install the 20mm Projex Damtec Sub Ballast Matting (SBM). The SBM was chosen because it has effective vibration absorption properties and additionally a significant structure-borne noise attenuation control factor; it cuts down on the amount of noise generated by the trains as they pass over the rail structure.

The 20mm SBM was installed for a distance of 850 metres to a width of 2.5 metres on both tracks. Both John Holland Rail and Public Transport Authority found the Projex Damtec SBM system extremely beneficial and easy to install.

Ballast installed over geotextile

Ballast installed over geotextile

Track installed over ballast

Track installed over ballast

Project completed

Project completed