The motorhome drove out into the intersection at the same time as the freight train passed, says Mattias Lindqvist at the Rescue Service Jämtland.
How fast the train was going is unclear.
But it is said to have been a very powerful collision, says Lindqvist.
It is unknown how many people have been affected in the accident.
The alarm came at 17.12 and has, according to the Swedish Transport Administration's website, caused major disruptions in traffic.
There is a lot of debris on the track that needs to be removed, and people who have seen this happen that one talks to.
