In actions against a railroad company for personal injury to a person while in its employ, or for death resulting from such injury, arising from the negligence of such company or any of its officers or employees, in addition to other liability, it shall be held that every person in the employ of such company, with actual power or authority to direct or control another employee is not the fellow servant, but superior of such other employee. Every person in the employ of such company who has charge or control of employees in a separate branch or department is to be held to be the superior and not fellow servant of employees in another branch or department who have no power to direct or control in the branch or department in which they are employed.