Peterson is a Canadian stage, television and film actor best known for his roles in Street Legal, Corner Gas and This is Wonderland.
He has also had small roles in The Umbrella Academy, American Gods and Street Legal.
Alex Ball portrayed the waiter serving Sheldon, Amy, Howard and Bernadette on the train.
This is not the first time Ball has appeared in The Big Bang Theory.
He played the same role in season seven, episode one, ‘The Hofstadter Insufficiency’, serving Bernadette and Amy at a hotel.
Ball is best known for playing Roy Brigham Anthony in Cold Case.
In Cold Case, he starred alongside Kathryn Morris, Danny Pino, John Finn and Tracie Thoms.
The Big Bang Theory is streaming on Netflix now
source: express.co.uk