A solution to Sydney's peak-hour train crush

New Transport for NSW commuter statistics show Sydneysiders make an estimated 1.2 million trips each day on our trains. Sydney's train system is moving more people by rail each day than every city in the United States, bar New York.

The city's annual rail patronage has increased strongly over the past decade, from 260 million in 2004-2005 to more than 365 million last year. Our trains are running at or over capacity in the rush hour.

People are shocked when I say Sydney is a city that depends on trains. Car is still king only if you exclude the postcode that generates the country's highest share of gross domestic product, Sydney's CBD.

Nearly 300,000 people work in the CBD, the vast majority of whom are commuters making return trips to and from the city. Given road congestion and a lack of parking we know we can't simply replace trains with cars to access the CBD. We would need to convert enormous areas into carparks to accommodate 300,000 more cars.

Yet, the cost of Sydney Trains remains too high, because half the rolling stock is kept idle outside of rush hour. Our double-decker trains are a custom-built oddity. And each train has a driver and a guard.

Employing guards has increased the cost of rail services and has historically acted as a brake to investment in expanding the rail network. If the right technology is adopted, the need for guards will decline. Most of the world's heritage systems have moved to driver-only operation. Many newly built lines are driverless.

Our double-decker trains are very difficult to run at a higher frequency than they do now. They have more seats but carry fewer people than single-deck metro trains. We need more trains with more room and rail lines or else our city will have a stroke.

The high-capacity driverless metro under construction offers a solution.

The new metro line is designed to carry 43,000 passengers per hour per direction (p/h/d). No Sydney Trains line can currently reach 20,000 p/h/d. Motorways only manage 2000 vehicles per hour per lane – mostly cars with one occupant.

The Sydney Metro – from Sydney's north-west to Bankstown – now under construction is an excellent idea and the Coalition governments should be praised for finally making it happen. Sydney Metro West from the CBD to Parramatta is also in the pipeline. But the Berejiklian government should keep moving in the right direction.

The City Circle tracks should be converted to metro and an all-stop metro line could run from Homebush through the City Circle to Revesby. This could be converted to carry a driverless metro like the Bankstown line or a metro with a driver, which wouldn't require the platform remakes of the Bankstown project but due to higher labour costs may be more expensive over time. Another pair of tracks, from Bondi Junction to Hurstville, is also ripe for metro conversion.

Together with the new line to Parramatta, these tracks would create a decent system for the most densely populated areas around the city. Metro conversions would facilitate the use of remaining tracks for longer distance, faster suburban trains with fewer stops.

The government should reconsider finishing the Maldon-Dombarton freight line and building a new tunnel under the Royal National Park escarpment for the fast train to Wollongong. Faster trains and limited express trains using improved or new infrastructure should also be considered to link Badgerys Creek and parts of western Sydney to Parramatta, Macquarie Park and the CBD.

A game-changing railway infrastructure could be the backbone of an efficient, sustainable system that will get everyone home for dinner on time without breaking the bank.

But this will only happen if the government makes the right moves to meet our growing use of trains and weans itself from an over-reliance on low-capacity, polluting motorways.

Associate Professor Pablo Guillen Alvarez is an economist at the University of Sydney. This article was first published in the Sydney Morning Herald.