A new rail freight line is being contemplated to unlock the economic development of Kwinana and Rockingham.

The WA Planning Commission is scheduled to consider today setting aside land for a potential new rail corridor.

It has been asked to approve rezoning about 126ha, including about 89ha as regional open space and Bush Forever and 19ha for railways.

The Department of Transport and Major Infrastructure wants the land set aside for potential use as a freight rail line.

It is intended to provide a connection between the Kwinana-Mundijong freight railway and the Cooperative Bulk Handling balloon loop, alleviating a bottleneck at a nearby railway junction known as the “Kwinana Triangle”.

A WAPC report said the freight rail network was operating at near-capacity and constrained by a single entry/exit point.

“Currently, high volumes of rail traffic from the north and south meet at . . . Kwinana Triangle,” it said.

“As this crossover point is currently at full capacity, this creates pressure on the road freight network and potentially limits economic development if this constraint is not addressed.”

New interchanges would lift Patterson Road, Mandurah Road and Day Road over the railway to avoid traffic interruptions.

There are no current commitments to actually build the rail line yet.

“This is a long-term land protection exercise that could be refined over time as the project moves through more detailed design phases,” a WAPC report said.

The City of Rockingham was invited to comment on the proposal in December.

Its suggestions included changing the designation of some roads so they would be under the control of Main Roads and not the city because they would involve significant bridges and heavy traffic.

WAPC planning staff have recommended against this, saying maintenance arrangements could be made with Main Roads.

The city also asked for more details about noise impacts and how they would be managed. Planning staff said this would be assessed in future design stages.

The Department of Biodiversity Conservation and Attractions asked that black cockatoo habitats be protected where possible.

The Department of Fire and Emergency Services was concerned the rail line would mean some properties would lose access.

“Impacts of this nature are manageable and capable of being addressed at a later stage when road and rail designs are further advanced,” the WAPC report said.

Main Roads warned it was planning a six-lane bridge over Patterson Road while the proposal assumed it would be four.

The Heritage Council would be consulted about what effects the proposal would have on the heritage-listed Day Cottage near Day Road.

The South Metropolitan Peel Sub-regional Planning Framework is currently looking for options for more freight rail infrastructure in the area.