The Kingston Flyer will host not only its first wedding but its first same-sex wedding in January, during a busy summer schedule of events for the vintage passenger steam train.
Flyer owner and managing director David Bryce said this week the men getting married were "ardent fans of steam-engine engineering, so they couldn't think of a better setting in which to say 'I do'."
The Flyer would provide the pre-nuptial transport, Mr Bryce said.
"In case of rain, we can certainly help them celebrate their wedding in style in one of our historic original carriages such as the Birdcage.
"I'm sure our driver will be happy to let them in on some secrets as we chuff our way between Kingston and Fairlight."
The second annual Race the Train event is set for January 6, with more than 300 runners and walkers expected to race the locomotive 12km from Fairlight to Kingston.
Organiser Adrian Bailey, of Active QT, said the event was close to his heart.
"I ran a similar event against a steam train near my home town in Wales for 10 years. While last year's inaugural event in Kingston attracted more than 200 runners, many have already signed up for this year's race and then some.
"They're coming from all over Australasia, so it's promising to be a huge line-up of professional and social runners and a great event.
"Friends and supporters can ride the train cheering the competitors on to the finish line, and the atmosphere is just fantastic. It's a great way to blow away the cobwebs after an over-indulgent Christmas and New Year."
After Christmas functions are finished, at the end of December, 1925 locomotive "778" goes out of service. Engineers in Invercargill are putting the final touches to "795", which will return with a newly restored boiler.
"It's a very expensive Christmas present to myself, but I'm not about to shy away from what needs to be done," Mr Bryce said.
"We knew when we bought the Flyer that we were investing in her for longevity. This is about ensuring the future of our history.