D.C. Code § 35-301

Every common carrier engaged in trade or commerce in the District of Columbia, or in any territory of the United States, or between the several states, or between any territory and another, or between any territory or territories and any state or states, or the District of Columbia, or with foreign nations, or between the District of Columbia and any state or states or foreign nations, shall be liable to any of its employees, or, in the case of his death, to his personal representative for the benefit of his widow and children, if any, if none, then for his parents, if none, then for his next of kin dependent upon him, for all damages which may result from the negligence of any of its officers, agents, or employees, or by reason of any defect or insufficiency due to its negligence in its cars, engines, appliances, machinery, track, roadbed, ways, or works.