§ 63. Persons employed as drivers, conductors, motormen or gripmen. Any railroad corporation may employ any inhabitant of the state, of the age of twenty-one years, not addicted to the use of intoxicating liquors, as a car driver, conductor, motorman or gripman, or in any other capacity, if fit and competent therefor. All applicants for positions as motormen or gripmen on any street surface railroad in this state shall be subjected to a thorough examination by the officers of the corporation as to their habits, physical ability and intelligence. If this examination is satisfactory, the applicant shall be placed in the shop or power house where he can be made familiar with the power and machinery he is about to control. He shall then be placed on a car with an instructor, and when the latter is satisfied as to the applicant's capability for the position of motorman or gripman, he shall so certify to the officers of the company, and, if appointed, the applicant shall first serve on the lines of least travel. Any violation of the provisions of this section shall be a misdemeanor.