21.—(1) In any mine of coal or fireclay no person shall use a locomotive for moving any vehicle otherwise than by hauling from in front, except during shunting operations.
(2) In any mine of stratified ironstone or shale no person shall use a locomotive for moving any vehicle otherwise than by hauling from in front except—
(a)during shunting operations; or
(b)for moving a single vehicle at a place within twelve hundred feet of a working face; or
(c)in a length of road in which a locomotive was used for hauling material before the first day of May, nineteen hundred and forty-nine.
(3) Where in any mine of stratified ironstone or shale any vehicle is moved by a locomotive otherwise than by hauling from in front in pursuance of sub-paragraph (c) of the last preceding paragraph, a white light visible at a distance of two hundred feet shall be attached to the front of the vehicle or, if there is more than one, of the leading vehicle: