One of the trains was loaded with dangerous materials, including flammable gas and a corrosive substance.
Police in Sweden have warned of a potential risk of explosion after two freight trains collided in eastern Gothenburg.
Police and rescue services were alerted to the scene at a railway yard in Sävenäs district on Tuesday morning.
One of the freight trains was loaded with dangerous substances, including ethylene oxide - a toxic and flammable gas - and hydrogen peroxide - a corrosive substance.
One train wagon has overturned but no leak has been found, police said in a statement.
It is unclear how large the quantities of the substances aboard the trains are.
No one was injured in the collision which occurred when the trains were being reconnected in the railway yard.
Authorities have cordoned off an area within a 600-metre radius of the accident site, and a nearby school and nursery school has been evacuated as a precaution. The railway station and all access roads have been blocked off.
The Swedish Transport Administration has announced that there are delays to travel at Gothenburg Central Station and several departures have been cancelled.
"The risk of explosion is very high, the situation is very serious," Martin Berntsson, fire inspector at Greater Gothenburg rescue services, told Swedish tabloid Aftonbladet.