Ella Johannessen, 23, was travelling to Leeds on a Virgin Trains East Coast service to visit friends on Saturday when a fellow passenger made the incredibly generous gesture.
After boarding at Peterborough, she sat down and phoned her mum to discuss a £35 bank transfer that had not gone through, while confiding in her about being short of money and worried about her financial situation.
Ella then fell asleep, and woke up half an hour later and noticed a napkin on her lap. When she looked under it, she found £100 in cash.
Posting on Facebook, she wrote:-
"I was incredibly thankful for your kindness to someone you don't even know. After a terrible 18 months where I lost my father and both of his parents, it shows me that there is kindness and good people in the world. I will pass your kindness on. I want to say thank you to the person who gave me this gift, I hope you will eventually see this."
Ella was a fine art student at Leeds Beckett University, and now works as a screen printer.