COASTAL RAILWAYS WITH JULIE WALTERS, C4, 8pm

CELEBRITIES love doing TV train journeys. Michael Portillo is at it. So is Chris Tarrant. Joanna Lumley has had a go, as has Griff Rhys Jones, and probably a zillion others I’ve watched and quickly forgotten.

The one thing that unites all of the above is exoticism. They travel across Siberia, Morocco, India and Japan.

Not so Julie Walters, who’s the latest celeb to do a train series for TV. Instead of sun, snow, sand, and spectacular scenery, she gets drizzly Scotland.

In the first of her new four-part series she climbs aboard the famous Jacobite steam train and takes a trip along the West Highland line.

This takes her across the glorious Glenfinnan Viaduct. Sadly, this calls for a bit of Harry Potter capering.

Then it’s onwards to the Isle of Skye where she meets a traditional Scottish storyteller.

EXPEDITION VOLCANO, BBC2, 9pm

SAY what you like about the BBC, but you can’t deny it is brilliant at natural history programmes. Tonight’s TV is a perfect example, with David Attenborough on BBC1 and this new series about the awesome power of volcanoes on BBC2. Sadly, it’s only a two-part series but I suppose Christmas is coming so we must make way for nonsense. The programme dispatches a team of scientists to have a poke around the world’s most smouldering, simmering, snarling volcanoes.

Tonight they visit Mount Nyiragongo, a worryingly active volcano in the Democratic Republic of Congo. But they’re not just there to gawp and send back some great footage of bubbling lava.

The locals want to know if another eruption is likely given that the last one, in 2002, wrecked a nearby city.

But their research is no easy feat, especially as the volcano lies in a war zone, meaning the team has a former Royal Marine assigned to it for its safety.