F1 Every tramway which is hereafter authorized by special Act shall be constructed on such gauge as may be prescribed by such special Act, and if no gauge is thereby prescribed, on such gauge as will admit of the use upon such tramways of carriages constructed for use upon railways of a gauge of four feet eight inches and half an inch; and shall be laid and maintained in such manner that the uppermost surface of the rail shall be on a level with the surface of the road; F2. . .