Kavau Teaukura arrives at Christchurch Railway Station on the Southerner from Invercargill in August 2001. The service wound up in February 2002.

South Islanders clamouring for a competitively-priced train trip from Christchurch to Dunedin shouldn't hold their breath.

Experts say the line would be difficult to run at a profit and would likely target the high-end tourist market if it went ahead.

Talk of resurrecting the passenger rail route has gained traction after it was announced KiwiRail was considering it as a replacement for the earthquake-affected Coastal Pacific route from Picton to Christchurch.

JOHN BISSET/FAIRFAX NZ Timaru Mayor Damon Odey is lobbying local authorities to support a passenger train service from Christchurch to Dunedin

The Southerner, a passenger rail service from Christchurch to Invercargill, via Dunedin, made its final journey in February 2002 after it was deemed unprofitable.

Timaru Mayor Damon Odey has taken to rallying southern mayors and tourism and economic development leaders to get behind the idea.

READ MORE:

* Mayors on board to discuss bringing back Christchurch to Dunedin passenger train

* Investigations but no progress on Christchurch-Dunedin passenger train, KiwiRail says

* Passenger train service between Christchurch and Dunedin a possibility, KiwiRail says

123RF.COM The famous Dunedin Railway Station.

Odey's approach aligns with the view of University of Auckland transport engineering group leader Douglas Wilson, who said there needed to be "a multi-party sort of agreement" with KiwiRail, local authorities and potentially the Ministry of Transport for the passenger service to happen.

The route would be a "high-value service where tourists are prepared to pay the extra dollars" to make it viable.

Services in the centres the route passed through would have to be improved, which would take time and involve commitment from communities, Wilson said.

JOHN BISSET/FAIRFAX NZ For the Christchurch to Dunedin route to work, experts say it'd need to target high-end tourists, meaning Timaru Railway Station, pictured, and other services would need a spruce up.

He also expected demand for the route "would take some time to generate".

"My greatest concern would be that doing something short-term would never be viable."

It was difficult to get both road and rail working efficiently in New Zealand given its small size and low population density, he said.

Victoria University of Wellington School of Management undergraduate programme director, Bronwyn Howell, said the service would have to be "high-end, luxury stuff aimed at the tourist market" to work.

Passenger rail was a difficult proposition in New Zealand as people tended to travel point-to-point, meaning operators only got one fare the whole way through, she said.

It differed from places where passenger trains were more popular, such as the United Kingdom and Europe, where people got on and off all the time meaning the same seats earn multiple fares.

As a passenger option, rail in New Zealand could not compete with air or bus travel for convenience, speed or price, Howell said.

"If there was an entrepreneur who was prepared to front up with the capital and a contractual arrangement that is low-risk to KiwiRail, then I may see it happen."

Boulter Consulting Urban and Transport Planning director Roger Boulter helped write a 2010 report looking at the economic case for developing a passenger rail network in New Zealand.

He said the report, which was commissioned by KiwiRail, found the Christchurch to Dunedin route was viable and believed it still would be now.

There would be some utility and transport use for the route, he said, but the main service would need to aim for "upmarket" tourists.

A KiwiRail spokeswoman said there were "no immediate plans for a service between Christchurch and Dunedin".

The company was always open to new services if they were commercially viable and a feasible business case would need to include "all infrastructure costs and a robust demand analysis", she said.