23. The joints of rails to be secured by means of fish-plates, or by some other equally secure fastening. On main lines, and lines where heavy traffic may be worked at high speed, the chairs not to weigh less than 40 lbs.; but on branch lines, or lines on which the traffic 29 is light, chairs weighing not less than 30 lbs. may be used. 24. When chairs are used to support the rails they must be secured to the sleepers, at least partially, by iron spikes or bolts. With flat-bottomed rails, when there are no chairs, or with bridge rails, the fastenings at the joints, and at some intermediate places, to consist of fang or other through-bolts; and such rails, on curves with radii of 15 chains or less, to be tied to gauge by iron or steel ties at suitable intervals. 25. In any curve where the radius is 10 chains or less, a check-rail to be provided. 26. Diamond-crossings, as a rule, not to be flatter than 1 in 8. 27. No standing work (other than a passenger platform) to be nearer to the side of the widest carriage in use on the line than 2 feet 4 inches, at any point between the level of 2 feet 6 inches above the rails, and the level of the upper parts of the highest carriage doors. This applies to all arches, abutments, piers, supports, girders, tunnels, bridges, roofs, walls, posts, tanks, signals, fences, and other works, and to all projections at the side of a railway constructed to any gauge. 28. The intervals between adjacent lines of rails, where there are two lines only, or between lines of rails and sidings, not to be less than 6 feet. Where additional running lines of rails are alongside the main lines, an interval of not less than 9 feet 6 inches to be provided, if possible, between such additional lines and the main lines. 29. At all level crossings of public roads, the gates to be so constructed that they may be closed either across the railway, or across the road at each side of the crossing, and a lodge, or, in the case of a station, a gatekeeper’s box, to be provided, unless the gates are worked from a signal cabin. The gates must not be capable of being opened at the same time for the road and the railway, and must be so hung as not to admit of being opened outwards towards the road. Stops to be provided to keep the gates in position across the road or railway. Wooden gates are considered preferable to iron gates, and single gates on each side to double gates. Red discs, or targets, must be fixed on the gates, with lamps for night use, and semaphore signals in one or both directions interlocked with the gates, may be required. At all level crossings of public roads or footpaths, a footbridge or a subway may be required. At occupation and field crossings, the gates must be kept hung so as 30 to open outwards from the line.