The government, which has yet to release a report into fast rail in the state that was delivered to it by a UK expert, says a rail program for the region is being "refined and defined".

Mr Hollis - whose group pushed for the first and second Bathurst Bullet services that travel to Sydney daily - says he has had discussions with Bathurst MP Paul Toole about track upgrades.

"I do believe they are looking at the rail line between Parkes and Sydney and how they can best improve the line so that we get a quicker service to Sydney," Mr Hollis said.

"It's something that I do push with Paul Toole in conversation and I have the feeling that it is on their agenda."

In May Mr Toole said the government was taking its time to get its rail strategy right, but the western route to Parkes (via Bathurst) had not been forgotten.

READ ALSO: Ray Hadley's Morning Show removed from Triple M Central West in 2021

He has emphasised previously, though, that the Parkes route is likely to get improvements to make it a "faster" route rather than a fast rail route.

Mr Hollis said there are a number of factors that need to be considered, including looking ahead at the possibility of rerouting the line altogether and, eventually, having a tunnel built through the Blue Mountains.

"There's a lot on the table," he said.

Mr Hollis expects train line improvements won't come all at once.

"They'll have to consider what's an appropriate budget to do this and I think it will be done in stages," he said.

"The first stage might be to improve the line between Lithgow and Parkes and then the second stage might be we do tunnelling through the Mountains down to Sydney. That's something for the future."

If a tunnel was to go ahead, effectively bypassing the Blue Mountains, access to Sydney from the towns in the Mountains would also need to be considered.

"You've got two aspects of it. One is the city rail service to still service the Mountains, and the other one is the overall service to connect Parkes more effectively with Sydney because that includes Bathurst," Mr Hollis said.

"I believe you want to have a look at the whole line between Sydney and Parkes and how you can best straighten it within a reasonable budget."

A Transport for NSW spokesperson said there are plans being developed to deliver a faster rail network.

"The NSW Government is investing $2.8 billion to replace our ageing XPT, Endeavour and XPLORER trains with a modern, new Regional Rail Fleet," the spokesperson said.

"The new trains will provide improved safety, accessibility, facilities and reliability for customers who travel from many NSW regional centres to Sydney."

The spokesperson said rail passing loops have opened at Rydal, Georges Plains, and Polona, near Millthorpe, acting as overtaking lanes to provide faster services, and more loops are being built at Pinecliffe, east of Manildra; Maryvale, near Wellington; and Bumberry, west of Manildra.

"Transport for NSW is committed to continuing to engage with communities, business and industry as the faster rail program is further refined and defined," the spokesperson said.

University of Wollongong associate professor in transport research Philip Laird said in an interview with ABC Central West last week that he would like to see contracts signed for train line upgrades before the next state election so people can say "it's not just another study, it's not just a promise".