Local resident Shelley Simonian has seen huge change in the past six years. Credit:Peter Rae The number of passengers passing through Green Square station on a week day is already estimated to have more than doubled in a year – from an average of 4810 in 2015 to 9766 last year. And that is before thousands of new apartments are built. Mathew Hounsell, a researcher at the University of Technology's Institute for Sustainable Futures who did the modelling, said the surge in apartments around Green Square meant the only solution was high-capacity public transport such as light rail. "No transport expert believes that buses can service the demand," he said. Transport Minister Andrew Constance freely admits Green Square is "public transport disaster" but blames the previous Labor governments for allowing a high concentration of apartments without plans for an "appropriate mass-transport solution". The City of Sydney has pushed the state government to commit to a light rail line from the central city to Green Square, and has spent $40 million buying land to preserve a 4-kilometre corridor from Central Station.

Patronage at Green Square in Sydney's inner south is estimated to have doubled in the past year. Credit:Peter Rae The challenge for the "Green Square urban renewal area" – encompassing Waterloo, Zetland, and parts of Alexandria and Rosebery – is plain in forecasts of a near tripling of its population from 21,000 people to more than 61,000 within 12 years. With 22,000 people packed into each square kilometre by 2030, it will easily become the most densely populated part of Australia. Patronage is soaring across Sydney's train network. Credit:Peter Rae At the moment, Pyrmont in inner Sydney holds the title with 14,000 people per sq km (the average across the city is 390 people).

Sydney Lord Mayor Clover Moore said residents in the precinct did not see public transport as a "looming disaster but one they experience every day". The area's population is forecast to almost triple over the next 12 years. Credit:Peter Rae "We had the foresight to acquire the corridor before land value and development made a light rail line near impossible, but the NSW government is responsible for Sydney's transport network – after years of lobbying them to build it, it's still not clear whether this essential project will go ahead," she said. "The government is enjoying the stamp duty rewards from apartment construction in this area, now it's time for them to provide ... essential services." Mr Constance said he would not rule in or out the government opting for a light rail line to Green Square, saying he did not want to pre-empt a transport master plan due later this year. "I have asked our agency to look at all options," he said.

However, he said short-term measures would have to rely on improvements to the bus network and encouraging "active transport" such as cycling. The Committee for Sydney told a federal transport inquiry last year that there was a "growing realisation that we are going to need to augment public transport in and around Green Square with a light rail service" – even with the existing heavy rail line from the airport and plans for a metro railway station at Waterloo. However, the advocacy group said the problem was funding a new light rail line because the government was unlikely to have money left over from constructing a $2.1 billion light rail line from the CBD to the city's south east and the new metro line. It has suggested the council impose a "special rate" on residents, which could raise more than $12 million in revenue a year. In addition to fares, it said a levy would "go a long way to repaying the cost of capital" required to build the line.

Local resident Russ Johnson has been catching the train from Green Square for the past three years, and "lately it has got a lot more densely populated at peak hour". "At peak hours in the morning you have to be in the right place at the right time. It's standing room only every day in the mornings," he said. "It's going to be like Tokyo and Hong Kong." The crowding was challenging because trains picked up passengers at Sydney Airport who carried large bags after arriving on flights. "They don't realise they are [about to get] on a peak-hour train," he said. Transport for NSW said it had made a concerted effort in recent years to ensure that public transport to and from Green Square kept pace with its development. Loading

Since 2011, an extra 400 weekly trips have been added to the M2 and 343 bus routes through the area – half of which began in February. Infrastructure Australia has put the need for better transport links between Sydney's CBD and Green Square among the country's top infrastructure priorities.