"Our volunteers have been working tirelessly since the NSW Government announced that museums could reopen from June 1," museum chairman Peter Meddows said.

"With three months' worth of long grass to cut and the intensive cleaning and preparations required, it has taken us a little longer to reopen safely.

"By Sunday, we will be able to welcome families back on to the site under safe conditions, offering displays and train rides for their enjoyment.

"At this time and until we are secure in operations our full-sized trains will be diesel-hauled.

"Steam locomotive Marjorie was placed in dry storage at shutdown and it is impractical to bring her back into service while our situation is uncertain."

While there is ample space in the grounds for visitors to safely move around, clear capacity signage will be posted for interior spaces in order to maintain social distancing.

The museum has also installed multiple hand sanitiser stations across the site to ensure proper hygiene.

Train carriages will also have specific occupancy limits and will be disinfected between journeys.

The museum's display rooms, canteen and souvenir shop will be open under strict social distancing guidelines.

"Our volunteer staff will soon be identified with blue vests, so that visitors can seek assistance more readily," Mr Meddows said.

"We are always open to the involvement of new volunteers to join our workforce and maintain the museum's operations and displays for the enjoyment of the community."

The museum is located at 262 Leggetts Drive, Richmond Vale (about four kilometres south of Kurri Kurri).

It is open on the first three Sundays of each month and school holiday Sundays from 9.30am.

Entry fees are adults $16.50, concession $11.00, children aged 5-15 $7.50 and under five free.