The pair, both 15-year-old boys from Swanley, Kent, were arrested on suspicion of attempted grievous bodily harm yesterday following the incident on a train running from Hastings, East Sussex, to London Victoria.
Both suspects were taken to a police station in Bromley and released on bail until Thursday, August 25, said BTP Inspector Gary Ancell.
A third teenager, a 16-year-old boy also from Swanley, was also arrested on Thursday and freed on bail until September 29, pending further inquiries by BTP officers.
The arrests follow the release of CCTV images of four youths police wanted to speak to over the attack on the Southern Trains’ service at about 6.30pm on Sunday, July 19.
The victim, a Swedish teacher visiting England with a group of her students, was walking through the carriage when one of a gang of youths held out a lighter and touched her hair.
She only realised her hair was on fire when she walked towards her students and they started screaming and pointing to her hair. The teacher was then able to pat out the flames.
The attack left part of her hair singed and although she did not suffer burns or need hospital treatment, the incident is said to have left her extremely distressed.