Five additional trains will haul coal along the suburban rail line every 24 hours if approval for the Wallarah 2 Coal Project is granted.

The environmental assessment for the proposed mine at Wyong will go on display today.

It shows that 5 million tonnes of coal would be transport by train to the Port of Newcastle for export every year when it reaches full capacity.

A State Government report in 2008 found the gates at Adamstown were closed more than six hours a day and Lord Mayor John Tate said the proposed mine would further compound an alarming problem.

"It is just going to be a disaster," Cr Tate said yesterday.

"There is an inefficiency with the rail line in Newcastle as it is and this will only make it more inefficient.

"They [Wallarah] say it includes plans for a Fassifern bypass but there is nothing marked on the plans and, anyway, it should have happened 10 years ago."

A project of the Wyong Coal Joint Venture, which has Japanese and Korean partners involved, the proposed mine would bring 300 direct and 700 additional jobs to the Central Coast.

Project environment and community manager Peter Smith said more than $1 billion would be invested into the Central Coast in the first three years of construction.

"The trains will operate at 80 per cent of what the bigger Hunter Valley trains do," Mr Smith said.

"They will be loaded with slightly less in each carriage which will make loading and unloading times more efficient.

"As for the time taken, that would be a matter for Pacific National or Q-rail [Queensland Rail] and the infrastructure in place."

Cr Tate was supportive of the proposed mine but insisted it was time for the State Government to act before the inner-city rail line became dangerously overloaded.

"The Wyong coalfields produce good quality coal and it is not far for it to travel to Newcastle," he said.

"But they should have a bypass built because the Newcastle rail line cannot function adequately for passenger trains with the amount of coal trains coming through Adamstown gates.

"It just demonstrates the Government's tardiness on this issue."