Ms MacTiernan told the Eastern Reporter the Department of Transport was researching the possibility of an underground railway line from the CBD to Morley
She said the project had been costed at about $2.8 billion, but more investigation was required.
Ms MacTiernan said underground rail was the way to go.
�I think this should be made public before the election so that we can have a mature discussion about this project,� she said.
Ms MacTiernan said the density in the area demanded the underground rail.
�Perth is on its way to becoming the congestion capital of Australia,� she said. �We need to look at tunnelling. The price has been driven down; boring machines are cheaper now.�
She said it was a better option than light rail or buses. �Light rail is important, but it is not adequate for moving the number of people in that area,� she said.
A Department of Transport spokeswoman remained tight- lipped about details.
�The strategic context for all future rail lines in metropolitan Perth is being further considered as part of long-term planning investigations for the Perth Transport Plan for 3.5 million people and beyond,� the spokeswoman said.
�The Planning and Transport Research Centre is conducting a mass transit study to form part of that plan.�