The Two More Trains for Singleton group recently asked coal companies operating in the Upper Hunter to support its push for additional services between Newcastle and Singleton.

The companies were also asked to consider contributing financially to the provision of two new carriages.

Group spokeswoman Pauline Davoren said the group received negative responses from BHP Billiton and Xstrata, which said they were unable to provide any support.

"The lack of support is disappointing, considering the health, educational, environmental and social benefits that the community and mine employees and their families would gain from better accessibility to services," Ms Davoren said.

She said improved passenger rail services would provide an opportunity for coalmine employees to travel to work by public transport, rather than travelling the increasingly congested and dangerous new England Highway by car.

"Given the enormous public investment in rail infrastructure for the benefit of coal mining companies, it is regrettable that appropriate passenger services cannot be provided," Ms Davoren said.

She said the NSW government was continuing to investigate the provision of additional services between Singleton and Newcastle in conjunction with the forthcoming completion of the Lower Hunter Regional Transport Strategy.