Olesya Belmasova and Anastasiya Kirillova, both 16, went to a train station in the city of Taganrog in southern Russia.
They tried to climb on the tank car of an old freight train that was standing at the platform – but didn’t realise it was still in use and on a live track.
The pair accidentally touched the track and were zapped with thousands of volts.
A horrified train worker who witnessed the scene said one of the girls appeared to ‘explode’.
He said: ‘I was walking towards them to ask them what they were doing when they were suddenly blasted to the ground.‘One was completely blackened and the other was on fire as if she had exploded.’
The pair were taken to a nearby children’s hospital with 70 per cent burns over their bodies and a number of fractures.
Anastasia, who was still able to talk, said: ‘We climbed on top of the tank car and then I heard a loud clap. We fell off the car and onto the ground.
‘My hair was on fire and I was in so much pain.’
Both girls are said to be in a serious condition.
A police spokesman confirmed: ‘They wanted to take some photos from the top of the tank car but were injured by a high-voltage electric current.’