The Butler Extension, Australia

The Butler Extension
Key facts
Product DAMTEC® SBM K 20 mm
System Sub Ballast Mat
Quantity 2,125 m²
Installation 2013
City Perth
Country Australia



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

Companies involved in this project:

Client: Public Transport Authority (PTA) – Perth

Contractor: John Holland Rail

Supplier of the 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 vibrations from passing trains. The vibration control was needed to protect the adjacent structures and buildings near a cutting where their passenger trains (max 28 tonne axle load) would be passing through.

If unchecked the vibrations could flow through the ground to the nearby houses that backed up to the top of the cutting, causing potential damage to those dwellings.

The solution was to install 20mm Projex Damtec Sub Ballast Matting (SBM). It was chosen because it has very good vibration absorption and additionally has a significant structure-borne noise attenuation 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 the “up” and “down” tracks. Both John Holland Rail and Public Transport Authority were very impressed with the ease of the installation. They found the Projex Damtec SBM system easy to install with a two-man crew.

Please find a few photos taken on site:

The Butler Extension

Workers installing 20mm SBM


The Butler Extension

Projex SBM tape over joints


The Butler Extension

Geotextile over 20mm SBM


The Butler Extension

Ballast installed over geotextile


The Butler Extension

Track installed over ballast

For all enquiries regarding Sub Ballast Mat in Australia please contact Projex group –


Posted on

30. October 2017