A BITTER and costly demar-cation battle between the Australian Workers Union and the Construction Forestry Mining and Energy Union could be in store for the successful tenderer for the $1.4 billion Perth to Mandurah rail project.

A BITTER and costly demar-cation battle between the Australian Workers Union and the Construction Forestry Mining and Energy Union could be in store for the successful tenderer for the $1.4 billion Perth to Mandurah rail project.