SECTION 1. If personal injury is caused to an employee, who, at time of the injury, is in the exercise of due care, by reason of—
First, a defect in the condition of the ways, works, or machinery connected with or used in the business of the employer, which arose from, or bad not been discovered or remedied in consequence of, the negligence of the employer or of a person in his service who had been in trusted by him with the duty of seeing that the ways, works, or machinery were in proper condition; or
Second, the negligence of a person in the service of the employer who was intrusted with and was exercising superintendence and whose sole or principal duty was that of suprerintendence, or in the absence of such superintendent, of a person acting as superintendent with the authority or consent of such employer; or
Third, the negligence of a person in the service of the employer who was incharge or control of a signal, switch, locomotive engine, or train upon a railroad; the employee, or his legal representatives, shall, subject to the provisions and of action against the employer as if he had not been an employee, nor in the service, nor engaged in the work, of the employer.
A car which is in use by, or which is in possession railroad corporation shall be considered as part of the ways, works, or machinery of the corporation which uses or has it in possession, within lite meaning of clause one of this section, whether it is owned by such corporation or by some other company or person. One or more ears which are in motion, whether attached to an engine or not, shall constitute a train within the meaning of clause throe of this section, and whoever, as part of his duty for the time being, physically controls or directs the movements of a signal, switch, locomotive engine, or train shall be deemed to be a person in charge or control of a signal, switch, locomotive engine, or train within the meaning of said clause.