I agree on the importance of the ability of workers to work in their language of choice, and it has a safety ramification. CN, if we're talking here about CN, has an obligation to ensure that all of its workers are able to work in their language of choice, and if it is not upholding that responsibility, the official languages commissioner is able to investigate and hold them accountable for potential failure.
To your point, I want to reiterate that safety is at stake, and not only rights. Safety is at stake and CN must fulfill its obligation.