The company that operates the only rail link between Broken Hill and Adelaide has confirmed it's cutting its seated economy class, sparking concerns about the outback city's increasing isolation.

The change would mean all travellers would have to purchase sleeper cabins on the Indian Pacific and the Ghan.

The cost of a Broken Hill pensioner's ticket to Adelaide would rise from $187 to $689.

A non-concession ticket on the same trip would rise increase from $399 to $689.

Last month the train's operator, Great Southern Rail said that the federal government's reduction in concession subsidies would mean increases to ticket prices, and a reduction in service frequency.

Local councillor Peter Black said the change would make it difficult for many Broken Hill people to travel to the nearest capital.

"Many people could not possibly afford to travel to places like Adelaide by air," Mr Black said.

"We need our train, we need the train to continue to be affordable to the people of Broken Hill."

Great Southern Rail said around 17 per cent of its customers on the Indian Pacific and The Ghan book seating rather than sleeping carriages.

"With [federal concession subsidies] withdrawn, GSR has had to make adjustments to its business," a spokeswoman said in a statement.

"GSR has committed to providing a 20 per cent discount to concession customers next year.

"There will, however, still be an increase for the price of travel, and we do expect there to be some reduction in demand."

Older people and pensioners who routinely use the Indian Pacific to get to Adelaide for medical appointments and shopping said the cuts leave them without a reliable link to the city.

71-year-old Menindee resident John Lasher uses the train to get home from Broken Hill as well as to Adelaide.

"You will get people boarding at Broken Hill who will get off at Ivanhoe, or Condoblin, or Euabalong West, or Orange East Fork, or Bathurst to Lithgow," Mr Lasher said.

"We have a lady...who travels on the [Indian Pacific] to Sydney four times a year and then she takes the train down to Wollongong, up to Newcastle, to visit her relatives.

"Then the next week she'll come back on the Indian on a Thursday morning.

"She can't afford to travel first-class."