RAILWAY CONSTRUCTION. 29 



lines on which the traffic is light, chairs weighing not less than 

 30 Ibs. 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 inter- 

 mediate 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 rail- 

 way, 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. 



