"The week long closure of the Blue Mountains closure of the railway line is another reason why the Blayney, Cowra, Young, Harden regional link line should be reopened," Mr Fischer told the Young Witness.

Transport NSW advised on April 2 that the Blue Mountains train line was out of service between Penrith and Springwood.

The line was closed after a huge boulder came away from the cliff face above the train line threatening the safety of the track below and did not reopen for more than one week.

"It's a classic case where you need extra rail resources to deal with emergency situations," Mr Fischer said.

"Whilst clearly the passenger trains would not have been diverted that way, Roger Fletcher freight trains from Dubbo to Port Bortany would have been able to use the line, instead they had to go way out to Parkes back to Stockinbingal and Cootamundra.

"This line can get a little congested," he said.

Mr Fischer said use of the line during the week of the closure could also have had tourism benefits.

"In any event the Bathurst Bullet train which runs on a Saturday and Sunday, with promotion as a one off scenic route from Bathurst to Blayney, Cowra, Young, Harden and onto Sydney and back that same route, would have been packed to to the gun halls with passengers," he said.

"This is national significant infrastructure, it is certainly NSW state rail infrastructure of importance," Mr Fischer said of the mothballed Blayney to Harden line. "Most of the rail is still in place although some bridges need to be repaired. The tunnel at Carcoar is in good condition, it's time to get on with it."

Member for Cootamundra Steph Cooke said during the State election campaign "it should never have closed to start with".

"Since (first) becoming elected, I have been working closely with Cowra and Hilltops councils for its re-opening. This project will significantly transform the agricultural economy of this region, boost jobs and remove trucks from our roads, shifting tonnes of freight onto the rail network.

"Five million dollars was announced in August 2016 for the Maimuru to Demondrille section of the line. This is still on the table and remains part of the Fixing Country Rail allocation.

"I am on the record as saying that a detailed engineering economic and social study needs to be undertaken."

Mr Fischer called on the mayor's of the council's campaigning for the re-opening of the line, including Cowra and Hilltops, to approach deputy prime minister and member for Riverina Michael McCormack to put re-opening the line back on the radar.

"The line has three key roles. Firstly, as a freight line, especially in harvest time and with the possibility of some mine freight. Secondly, it could be a relief line for the main western and main Melbourne lines. And finally as an anchor for the huge potential upsurge in rail heritage tourism," he said.