Wherever the height of any embankment, or depth of any cutting, shall exceed 5 feet, the extreme height over or depth beneath the surface of the ground must be marked in figures upon the section. All tunnels and viaducts must be shown on the section. At a junction with an existing railway, the gradient of such existing railway must be shown on the section on the same scale as the general section for a distance of 800 yards on each side of the point of junction. Where the level of any turnpike or public road has to be altered in making any railway, the gradient of any altered road need not be better than the mean inclination of the existing road within a distance of 250 yards of the point of crossing the railway; but where the existing roads have easy gradients, then the gradients of the altered roads, whether carried over, or under, or on the level with the railway, must not be steeper than 1 in 30 for a turnpike road, 1 in 20 for a public carriage road, 1 in 16 for a private or occupation road. A good and sufficient fence, 4 feet high at least, shall be made on each side of every bridge, and fences 3 feet high on the approaches. The application to cross any public road on the level must be reported upon by one of the officers of the Board of Trade, and special permission for the work must be embodied in the Act. Not more than 20 houses of the labouring classes may be purchased in any city or parish in England, Scotland, and Wales, or more than 10 such houses in Ireland, until approval has been obtained to a scheme for building such houses in lieu thereof as the authorities may deem necessary. Every bridge (unless specially authorized to be otherwise) must conform with the following regulations:-- A bridge over a turnpike road must have a clear span of 35 feet on the square between the abutments, with a headway, or height, of 16 feet for a width of 12 feet, as shown on Fig. 12. [Illustration: Fig. 4.] A bridge over a public road must have a clear span of 25 feet on the 12 square between the abutments, with a headway of 15 feet for a width of 10 feet, as shown on Fig. 13. A bridge over a private or occupation road must have a clear span of 12 feet on the square between the abutments, with a headway of 14 feet for a width of 9 feet, as shown on Fig. 14. Road bridges over the railway must have the same clear width between the parapets, measured on the square, as the widths prescribed for road bridges under the railway, or 35 feet for a turnpike road, 25 feet for a public road, and 12 feet for private or occupation road.