They represented CN workers in 2022. However, unionized workers cannot sue their employers directly. It's a common sense in Canadian labour law. The lawyer obviously didn't know this knowledge. The case was rejected by the court.
I think it's important to know whether the lawyer is competent before one participates.
Ref:
https://canadianmale.wordpress.com/2022/03/26/200-cn-workers-file-against-feds-rail-company-for-vaxx-mandate-firings/