This month one of New Zealand's most treasured trains, the TranzAlpine Express, turns 30.

The TranzAlpine is renowned worldwide for its stunning scenery, as it cuts and weaves through the South Island's Southern Alps.

Today, Kiwirail operated a special service to celebrate the train's birthday.

Several of the original staff were on the train, telling tales of the good old days working on the TranzAlpine when the first train left the station in November 1987.

Among them was the train's first manager, Bob Ewing.

"We were as green as grass on the first day," he said. "Everything went right, we had helicopters flying beside us full of journalists ... it was a new ball game."

The 223km journey took about five hours, passing through deep valleys and some of the country's most beautiful landscapes.

It started as a converted passenger train and quickly increased in popularity - 30 years on, it has been crowned by international media as one of the most scenic rail journeys in the world.

Garry Kelly drove the train in the late '90s, and said it was an incredible experience.

"I used to have several people I would hoot the old whistle too ... one woman called me the horny engine driver."

He said he was proud of the title.

Today's journey was not only a birthday celebration, but a celebration of the train's survival.

Earlier this year, the train was forced out of action for several weeks, after a fire tore through some of the track, bridges and signal systems near Springfield.

But the route was quickly repaired.

One of the visionaries behind the train, John Bennett, said it was not easy to establish the service.

"Rail had no credibility at that point, that was the big battle ... we wanted to ensure that the TranzAlpine was used," he said.

But 30 years later, Mr Bennett still believed rail was the future of transportation.

In the year to June 2017, about 110,000 people travelled on the TranzAlpine Express.