Welcome to future Sydney; where your car registration is cheap, toll roads were abolished and the trains are on time.

It sounds a distant, utopian dream, but academics and transport experts hope one day it will be the reality, and argue the solutions to the harbour city's railway woes lie off the tracks.

Sydney's train system has been called many things in the past week — a debacle, chaotic, third world.

Professor David Hensher, from the University of Sydney, is the founding director of the Institute of Transport and Logistics Studies and believes he has the answers.

Sydney's Central Station is Australia's busiest railway hub. ( ABC News: Amanda Hoh )

His blueprint includes getting rid of the city's 11 toll roads and halving the cost of car registration.

Unsurprisingly, there's a catch — despite those cost-saving measures, in the long run, Professor Hensher wants to make driving harder.

"We have done an appalling job of pricing the use of the car," he said.

"Until such a time as we can get that right, the adage is 'to make public transport more attractive, you've got to make the car less attractive'."

Our transport is linked

Researchers argue the solution to fixing Sydney's train and broader transport issues are linked to our roads.

The Grattan Institute's transport policy director Marion Terrill said people in buses, trains and cars had the same goal.

"The most important thing is that people can get from where they are, to where they want to go in a reasonable time and reliably," she said.

"How you do that, is a secondary issue."

Professor David Hensher, from the University of Sydney. ( Supplied: David Hensher )

Both Ms Terrill and Professor Hensher believe putting a price on congestion holds the key.

While their views differ on exactly how that should be implemented, they both believe asking drivers to pay to use the roads at peak times is the most effective way to fund all transport in the future.

Congestion pricing is not exactly a new idea, but slashing registration is — more on that later.

Colin Schroeder, co-convenor of the public advocacy group EcoTransit has a more hard-line approach.

While the NSW Government spruiks its $16.8 billion WestConnex development as "the world's biggest road project", Mr Schroeder is not getting swept up in the excitement.

"WestConnex should be stopped," he said.

"All it's going to do is bring more traffic into the city and where is that traffic is going to go? There's no parking."

He argues that money would be better spent investing in public transport.

"That's one of the excuses of treasury for building roads, because governments can get revenue from toll roads, they can find the money to build them," Mr Schroeder.

"But all the money that's being spent on WestConnex could build a lot of light rail or heavy rail.

"We're totally against expansion of the motorway network. They take people off the trains, then the roads clog up so people turn to rail."

But according to Mr Schroeder, there's a bigger problem.

He said major NSW Government rail projects like Sydney Metro — which is under construction — and Metro West — a proposed new line between the CBD and Parramatta — would provide only temporary transport relief in the rapidly expanding capital.

Mr Schroeder claimed transport policy in Sydney was based around development potential, not fixing congestion.

"Look at Sydney Metro, they're building high-rise developments from Sydenham to Bankstown, because there's huge development potential and that's where the metro is going," he said.

"It's not about solving Sydney's transport needs, it's about seeing how many more people we can cram into the Sydney basin."

About 35,000 new dwellings are proposed between Sydenham and Bankstown, but Mr Schroeder said some modelling predicted double that.

So why cut rego?

Professor Hensher's modelling reveals what could happen if Sydney's tolls were scrapped and drivers were charged for being on the roads between 7:00am and 9:00am every day, and again in the busiest two hours each evening,

If motorists paid a flat rate of 5 cents per kilometre for driving during those times, he argues the NSW Government would be no worse off.

Halving car registration is an important part of his plan, because it would soften the financial and psychological blow to motorists who already believe they're paying too much.

Sydney's congestion has been put under the microscope by academics. ( ABC News: Luke Rosen )

Professor Hensher said his research has suggested that would lead to a 6 per cent reduction in cars on the roads in peak times.

"That's just enough to deliver a peak traffic level similar to what you experience in school holidays," he said.

"That's phenomenal."

The plan is not a quick fix.

Professor Hensher claims a charge of 5 cents p/km would maintain the status quo.

To improve things, the NSW Government would need to increase that fee over time.

It would be much easier to make changes to the universal charge, compared to the varied toll system and charging methods in place today in NSW.

But even a 1 cent increase would deliver 20 per cent more revenue, which Professor Hensher said could be injected into road and rail infrastructure.

The hypothetical long-term benefits are obvious, but there are also drawbacks.

Any increase to the 5 cents p/km charge would naturally incur a voter backlash, where several marginal, car-only western Sydney seats could change hands.

As people abandoned their cars, the city's already stressed train networks would be put under enormous pressure, and building rail infrastructure takes time.

Sydney's population has swollen 20 per cent in the past decade, while train patronage is up 11 per cent in the past year.

"I would go so far as to say $200 or $300 billion is going to be required to really make a difference going forward in the next 10 or 20 years," he said.

Ms Terrill described congestion pricing as a "big opportunity".

"It's obvious that the rail system is under increasing capacity pressure and given Sydney's population growth is not slowing, you kind of need to keep on pulling out more tricks," she said.

Sydney's train meltdown last week cause widespread delays and crowded platforms. ( ABC News: Clare Blumer )

"For that reason I think it's time for the NSW, and the Victorian Government for that matter, to think about congestion pricing."

One of the big stumbling blocks of such an overhaul would be renegotiating the existing agreements with private toll road operators.

"The biggest problem with tolls is that we're locking in these arrangements for 30 or 40 years and the world is changing in quite unpredictable ways," Ms Terrill said.

"Having a very rigid plan for the future may not serve us well in decades to come."