GEOFF BENNETT: You know the sight and the sound, the heavy sigh of a sleek steam engine coming to rest at a station in an old film.

And you might wonder what the connection could be from that vintage technology to today's war in Ukraine.

The belching fiery plants of these behemoths are fired by coal, and the price has skyrocketed since Russia's invasion.

In turn, that is jeopardizing the future of some of Britain's living and breathing museums, the country's heritage railway lines powered by coal, fire and steam.

From Southwestern England, special correspondent Malcolm Brabant reports.

MALCOLM BRABANT: They're burning through money at the Swanage Railway, as is every historic line in the land which gave birth to steam trains.

The locomotive hauling today's service is a 1940s vintage express, back to robust health after a $400,000 refit.

In total, there are 150 heritage railway lines in Britain, and all of them are facing the same problems.

This is the start of the new season, and they're all banking on good visitor numbers to help them survive.

GAVIN JOHNS, Chairman, Swanage Railway Trust: We have had to work very hard to address the impacts of the pandemic.

And coming out of that, we have still got major challenges ahead of us.

MALCOLM BRABANT: Leading the effort to keep this living museum on the right track is Gavin Johns, who has more than 30 years' experience with Britain's modern rail network.

GAVIN JOHNS: We have got two challenges, one, rising costs and the impacts of those rising costs on our customers.

So, our own costs are going up significantly, most notably, coal.

MALCOLM BRABANT: Three years ago, the daily spend on coal was $670.

Today, it's $1,600.

GAVIN JOHNS: Coal is a major issue for us, because, before the war in Ukraine, we were sourcing our coal from Russia.

So we had -- very quickly had to work with our supplier to switch the source of the coal.

MALCOLM BRABANT: Can you ever go back to Russian coal?

GAVIN JOHNS: I think its very unlikely that we will go back to Russian coal supplies.

We have been working hard to find new sources.

And I think, for the time being, that we will stick with those sources.

MALCOLM BRABANT: Johns says that ethical considerations, and not just sanctions, dictate the railway's stance.

Although costs have more than doubled, it'll try to absorb the hit and not raise ticket prices, because visitors are also struggling financially.

The hope is that more passengers like Matt Collins will turn up for a steam fix.

MATT COLLINS, Hotelier: Marvel at what steam engines were at the time.

Basically, it's controlled explosions, a real lesson in engineering.

And it's really evocative, the smells, the sights and the sounds, as you travel on these trains.

And it just gives you an insight into what the Victorians did for us.

MALCOLM BRABANT: While steam engines pump out carbon dioxide, along with water vapor, the biggest environmental impact of the locomotive age was to encourage air pollution by other heavy industries.

Today, the influence of heritage lines on climate change is negligible.

The railways insist they're using cleaner coal where possible and are trying to reduce their carbon footprint elsewhere.

In Swanage, aficionados like Suzanne Wiseman have no qualms about keeping steam alive.

SUZANNE WISEMAN, Passenger: It means a lot to me, because I was brought up in the steam railway era.

And we were just saying, actually, I remember standing on the railway bridges just watching them go under, and the driver used to always give us a peep and wave.

And it's just nice.

It's keeping a bit of the British heritage going.

I think people all over the world love us for our history, and this is a big part of it.

MALCOLM BRABANT: This heritage line benefits from being in a region that's popular with vacationers and day trippers.

Nevertheless, it's laid off a handful of permanent staff.

Other railways have been harder-hit and have been forced to make more drastic cuts.

STEVE OATES, Chief Executive, Heritage Railway Association: Railways have been using timber, steel for all the repairs, track renewals, locomotive and carriage renewals and so on.

So the cost of these sorts of commodities have all shot up.

So, yes, there are some railways at risk, absolutely.

MALCOLM BRABANT: As chief executive of the Heritage Railway Association, Steve Oates has an overview of the sector's myriad problems.

So, how would you categorize it?

STEVE OATES: It's tough.

It's looking tricky, because the economic challenges that everybody is facing and the cost of living crisis, which is affecting potential visitors, it's almost like a double or triple whammy.

MALCOLM BRABANT: Third-class travel is a concept that many British people can now grasp, as their living standards decline and they cut back on luxuries.

But Oates hopes that the allure of steam will prevail.

STEVE OATES: I think people will reluctantly put hands in pockets, as they did during COVID.

But it is a risk.

There's no question about it that there is a risk.

And railways do need to be really careful about this.

MALCOLM BRABANT: Even the popular Bluebell line, 130 miles east of Swanage, is not immune.

It relies on volunteers like Patricia Beale, who spent a lifetime working on modern railways.

PATRICIA BEALE (Station Foreman): It's something that gets in your blood.

I mean, I love railways and steam engines, the smell and just the general ambiance.

Steam engines are living creatures, or they appear to be living creatures.

They breathe.

MALCOLM BRABANT: Love and tender care have helped this Terrier class locomotive survive its contemporaries.

Now 150 years old, this is the little engine that could help pull the Bluebell over the economic mountain.

The railway's chairman is Paul Churchman.

PAUL CHURCHMAN, Chairman, Bluebell Railway: Morning.

Everything OK?

MAN: Yes.

PAUL CHURCHMAN: Ready for a busy day?

MAN: Hopefully, yes.

PAUL CHURCHMAN: Good.

MAN: Weather is not looking too bad at the minute.

PAUL CHURCHMAN: No.

Hopefully, we should have enough people in today.

We're working very hard, but we have to be realistic in that it's going to be very challenging.

MALCOLM BRABANT: The Bluebells' costs have also doubled because of the war in Ukraine, even though this coal doesn't come from Russia.

PAUL CHURCHMAN: Last year wasn't that good because of the rising costs and the softening of revenue.

We expect to post a loss for last year.

This year, we probably will post a loss again, but we are taking actions to get our business to break even for 2020.

MALCOLM BRABANT: The Bluebell and other lines can no longer rely on pure nostalgia as a crowd-puller.

They need to wrench young people away from the screens of their devices.

Nineteen-year-old Luke Hopgood, no longer volunteers, but keeps coming back.

LUKE HOPGOOD, Former Bluebell Volunteer: There's just old-fashioned stations, and it's just very traditional.

And there's just a very authentic feel about it.

MALCOLM BRABANT: This station is a favorite with film producers.

It featured in the "Downton Abbey" series, but the Bluebell can't rest on its laurels.

PAUL CHURCHMAN: People don't want to just come for a train ride anymore.

It needs to be so much more than that.

You need to have the added value to the day out in the visitor experience.

GAVIN JOHNS: We have got a steam gala coming up in a few weeks with some great engines coming, which we know will attract enthusiasts.

MALCOLM BRABANT: The Swanage line was axed from the British network in 1972.

Gavin Johns has no intention of letting it die a second time.

GAVIN JOHNS: We have got a great set of volunteers who help the railway out.

We have got a great set of staff that work really hard to keep things moving.

And I think that, with our special events and with the determination, and we have got a really good chance of surviving.

MALCOLM BRABANT: This summer, in a new initiative, this heritage diesel train will connect to mainline services for the first time in 50 years.

The message from all 150 historic railways is the same.

PAUL CHURCHMAN: Come here.

Spend your money.

(LAUGHTER) PAUL CHURCHMAN: Help us survive.

Enjoy the experience we have.

It is unique.

MALCOLM BRABANT: Can they make it?

They think they can.

They think they can.

For the "PBS NewsHour," I'm Malcolm Brabant in Southern England.