It's part of a scheduled three-day program involving 109 jobs to help deliver service reliability, according to the Australian Rail Track Corporation (ARTC).

The work will be undertaken from the port at Kooragang and along the rail corridor to Narrabri, as well as the Ulan line west from Muswellbrook.

ARTC group executive for the Hunter Valley Network Jonathan Vandervoort said maintenance works along the network included track realignment, re-railing and track reconditioning.

"There is a large re-railing project at Newdell," he explained.

"Workers will be laying 98 110m lengths of rail.

"This is one of the biggest re-railing projects in the Hunter network this year.

"Track reconditioning will occur at Sandgate, Hexham and Lochinvar, while there will be realignment works in Muswellbrook and a turnout renewal at Quirindi."

In order for the work to occur efficiently and safely, Mr Vandervoort said a shutdown on the network would be in place.

"Similar to other recent maintenance programs, a scheduled shutdown is required to allow us to access the track for maintenance and upgrades that cannot be done safely when trains are running," he added.

"The work will generally start at 6.30am on Tuesday, September 24, and is expected to be completed about 6.30am on Friday, September.

"We apologise for the inconvenience and, as always, we appreciate the patience and cooperation of motorists, commuters and customers right across the maintenance program.

"We also ask people in communities close to the rail corridor to be cautious during the shutdown period and keep an eye out for increased vehicle movements in and out of work sites."

With the shutdown affecting Hunter Valley train services, alternative bus services will be provided, and details and schedules can be found at the Transport for NSW website.