In any action brought against any common carrier, under or by virtue of § 8.01-57, to recover damages for injuries to, or death of, any of its employees, the knowledge of any employee injured or killed of the defective or unsafe character or condition of any machinery, ways, appliances, or structures of such carrier shall not of itself be a bar to recovery for an injury or death caused thereby, nor shall such employee be held to have assumed the risk of his employment in any case in which the violation by such common carrier of any statute enacted for the safety of employees contributed to the injury, or death of such employee.