The Swedish Transport Administration (Trafikverket) warned on Monday that motorists should be careful on the roads as temperatures plummeted over the weekend and the freeze continued into Monday.
The train line between Halmstad and Laholm in the south has been out of action since 6am when a train with 13 passengers derailed after hitting a snowbank. All the passengers escaped unharmed.'
"It wasn't so dramatic. But the train remains where it is," Peter Behrman, spokesman at Trafikverket, told the TT news agency. He added that the line should be running as normal by Tuesday.
Sunday night saw the lowest temperature of the season when Karesuando in the far north hit -41.9C, but the mercury didn't stop there.
"It was -42.5C in the early morning hours," said Lisa Frost, meteorologist at Sweden's weather agency SMHI. "The high pressure system is still hanging over northern Scandinavia. These temperatures are here to stay for the coming days."
Train traffic north of Boden remains cancelled, a move national operator SJ makes when temperatures dip below -30C. Even the buses remain cancelled.
Swedish trains lines are shut down in extreme cold as the metal tracks can become brittle and risk being damaged, and because potential evacuations of carriages can be difficult in the largely isolated parts of northern Sweden.