Federal and state governments now acknowledge housing affordability as one of the most pressing issues faced by Australian cities. It is also certain to be a key election concern, with the Greens firing the opening shot with a controversial $12 billion housing policy. But the urgency to find solutions is leaving good options out of the discussion.

NSW Premier Chris Minns has declared our state’s investment in Sydney Metro should be used to increase density and affordable housing by announcing eight metro stations and 31 heavy rail stations for targeted density increases.

The delivery of this vision is still left to private developers on private land and can only occur at the rate the market can absorb for-sale apartments, which in the present market conditions is slow. If we want to make a substantial shift in the housing crisis, another solution is needed: combining the best of the public and private sectors to work together.

As an alternative, the state government should be releasing development rights to build over-rail corridors within five minutes’ walking distance, or 400 metres, of a rail station. Rail corridors themselves are a massive state government land asset, which are by definition adjacent to public transport.

Two suburbs that don’t just meet the criteria but are primed and ready for over-rail development are Newtown and Burwood. Why not start here?

Development over rail follows a simple sequence: a prefab land deck is built over the rail infrastructure, minimising disruption and allowing quick after-hours construction without affecting train schedules. Residential apartments can be constructed on top using modular techniques, facilitating rapid assembly and potential disassembly. Prefab housing modules could be stacked to create diverse housing types, from towers to courtyard housing.

The Burwood rail high-rise development as proposed by Bates Smart.

This is not a radical concept as international examples at Hudson Rail Yards in New York and Kings Cross in London attest. In Australia, we just need to look to Melbourne where Federation Square and Fairfax Headquarters demonstrate this technology. In Sydney, it has already been done at St Leonards to create a new park and is proposed for the development over Central Railyards. So, what’s stopping us?

The land component of housing equates to about 35 per cent of the total cost. If the state government released the air-rights over-rail, the land cost would be eliminated. This housing could be delivered under a public private partnership (PPP) between the state and a build-to-rent developer. The state would tender the land, with a stipulation that 35 per cent of the housing should be affordable. The market rent housing would offset the cost of the affordable housing, allowing more than the 35 per cent minimum to be provided.