The victim, who is in his mid-twenties, was hit by the train at 10.10pm on Tuesday at Stockholm’s central underground station (T-centralen) on the southbound platform for the busy green line.
Police launched a probe into suspected attempted murder after claims he was pushed by another man.
On Wednesday afternoon they released an image of an individual caught by surveillance cameras, appealing for anyone with information to contact them. However, when asked by The Local, they would not confirm whether or not he was being treated as a suspect, saying only that he “could be a suspect”.
A man, understood to be the man in the CCTV image, was later seized by police shortly after 5pm, after witnesses recognized him in the Rinkeby suburb north of Stockholm.
The victim's partner and witnesses are understood to have told police that he was pushed onto the tracks from behind. He was being treated at the Karolinska University Hospital on Wednesday. His injuries were described as serious, but were not believed to be life-threatening.