Each railroad shall equip each of its track motor cars used during the period from sunset to sunrise with (1) an electric headlight of such construction either permanent or portable and with sufficient candlepower to render plainly visible at a distance of not less than three hundred feet in advance of such track motor car any track obstruction, landmark, warning sign, or grade crossing and (2) a red rear electric light of such construction and with sufficient candlepower as to be plainly visible at a distance of three hundred feet. Such track motor cars shall be equipped with a shield of sufficient width and height to afford reasonable protection to the employees transported by it, part of which shall be a windshield of transparent shatterproof material.