OSL Early Flight (0600) - where to stay

I have an early flight out of OSL Friday morning at 0600. I am flying in from TOS the night before and am wondering if I should stay at the airport hotel (radison) or if I would have enough time to take the train from the center in the morning. The train schedule shows the first train leaving at 0440 which would get me to OSL by 0502. Is that enough time to get through security and to boarding?