of a train, car, engine, or switch, or in any service requiring his presence upon a train, car or engine, and every such employee shall have the same right to recovery for every injury suffered by him from the acts or omissions of any other employee or employees of the common master, that a servant would have (at the time when this Constitution goes into effect), if such acts or omissions were those of the master himself in the performance of a non-assignable duty provided, that the injury, so suffered by such railroad employee, result from the negligence of an officer, or agent, of the company of a higher grade of service than himself, or from that of a person, employed by the company, having the right, or charged with the duty, to control or direct the general services or the immediate work of the party injured, or the general services or the immediate work of the co employee through, or by whose act or omission he is injured, or that it result from the negligence of a co employee engaged in another department of labor, or engaged upon, or in charge of, any car upon which, or upon the train of which it is a part, the injured employee is not at the time of receiving the injury, or who is in charge of any switch, signal point, or locomotive engine, or is charged with dispatching trains or transmitting telegraphic or telephonic orders therefore, and whether such negligence be in the performance of an assignable or non assignable duty.  The physical construction, repair or maintenance of the roadway, track or any of the structures connected therewith, and the physical construction, repair, maintenance, cleaning or operation of trains, cars or engines, shall be regarded as different departments of labor within the meaning of this section.  Knowledge, by any such railroad employee injured, of the defective or unsafe character or condition of any machinery, ways, appliances or structures, shall be no defence to an action for injury caused thereby.  When death, whether instantaneous or not, results to such an employee from any injury for which he could have recovered, under the above provisions, had death not occurred, then his legal or personal representative, surviving consort, and relatives (and any trustee, curator committee or guardian of such consort or relatives) shall, respectively, have the same rights and remedies with respect thereto as if his death had been caused by the negligence of a co employee while in the performance, as vice-principal, of a non assignable duty of the master.  Every contract or agreement, express or implied, made by an employee, to waive the benefit of this section, shall be null and void This section shall not be construed to deprive any employee, or his legal or personal representative, surviving consort or relatives (or any trustee, curator, committee or guardian of such consort or relatives), of an\ rights or remedies that he or they may have by the law of the land, at the time this Constitution goes into effect Nothing contained in this section shall restrict the power of the General Assembly to further enlarge, for the above named class of employees, the rights and remedies hereinbefore provided for, or to extend such rights and remedies to, or otherwise enlarge the present rights and remedies of, any other class of employees of railroads or of employees of any person, firm or corporation