the workman’s endeavour to avoid damaging the point of his augur by forcing it entirely through the sleeper, and bringing it in contact with a stone. Augur-holes bored wide to gauge will remain out of gauge, and although the spike may be driven down firm in its position, a space will be left for play between the rail-flange and spike.
[Fig. 329] is a sketch of a dog-spike for flange rails which the writer has used for many years both abroad and at home, and which can be driven without any boring at all. The back of this spike is made perfectly straight, half of the front side is made parallel to the back, and the remainder is tapered down to a chisel point not exceeding 1/16 of an inch thick, the entering edge on the face being narrowed down to 3/8 of an inch in width. Three jags or spurs are cut on each side of the tapered portion, or twelve in all, and add greatly to the holding power. Not only can this spike be driven without any boring, but it possesses the additional advantage that in driving it down its taper or wedge-like shape causes it to drift hard up to the edge of the flange of rail, an element of great value in securing the exact gauge of line. With these spikes permanent-way laying can be carried on very rapidly, and they are especially valuable when making alterations, as augurs for spike-boring can be dispensed with altogether.
Wood screws with square heads similar to [Fig. 330] are sometimes used for fastening flange rails to wooden sleepers. They are passed through holes punched or drilled in the flanges of the rails, and are intended to preserve the gauge as well as secure the rails to the sleepers. Experience has shown that these wood screws possess very limited holding power. The screwed portion of the bolt cuts but a very imperfect and weak holding thread in the soft wood of an ordinary sleeper, moisture insinuates itself into the bolt-hole, rusting the bolts and decaying the surrounding timber, and in a very short time the bolts become loose and incapable of holding the rail down firmly. As permanent-way fastenings wood screws are very inferior to crab bolts.
Crab bolts, as in [Fig. 331], may be made either with square or hexagonal heads, and with three spur-nuts or four spur-nuts, as in A or B. The length of the bolts will depend upon the thickness of the sleeper or timber-work through which they have to be inserted. The bolt is pushed down through the hole bored in the sleeper, and the crab-nut put on from underneath.
With a few turns of the bolt, the crab-nut is brought close up to the under side of the sleeper, the spur-points become embedded in the wood, and hold the nut firmly in position during subsequent tightening of the bolt. Crab bolts are extensively used with flange or flat-bottomed rails, and also in switch chairs and in crossings. A large number of flange rails are used with one hole through the flange at each end of rail, and a crab bolt passed through the hole and through the sleeper next to the joint, as shown in [Fig. 332]. This system checks the creeping of the rails by effectually securing or anchoring each rail to two of the sleepers. As there is always a tendency for these rails to crack through to the outside at the flange-holes, it is very desirable to have as few holes as possible. The two above described will be found sufficient for all practical purposes. To avoid punching or drilling more holes in the flanges of the rails, additional or intermediate crab bolts can be used by means of the fang clips shown on [Fig. 333]. The crab bolt is passed through the fang clips and through the sleeper close up to the flange of rail, and by screwing it round in the crab-nut under the sleeper the fang-clip is pressed down until the two spurs are driven into the timber, and the rail held securely in its place and to gauge. Intermediate crab-nuts and fang-clips should always be used in pairs, one on each side of the rail. Possessing more holding-down power than ordinary spikes, they are particularly valuable on sharp curves.
In some cases flange rails are laid in small cast-iron saddles, or chairs, as shown in [Fig. 334], one end of the rail-seat having a recess to prevent the rail tilting upwards and outwards. An ordinary spike may be used for the inside end of chair, and a crab bolt with bent washer for the other. Unless the fastenings can be kept always tight, the above arrangement makes a very noisy, clattering road, as there are so many metal surfaces in contact, and so little to deaden the vibration. For narrow flange rails carrying heavy rolling load, chairs may be necessary to increase the bearing surface on the sleeper, but with rails having flanges five inches wide and upwards, it is better to let the flange rest direct on the wood of a properly grooved sleeper, and thus obtain a smoother and less noisy road.
On exceptionally sharp curves, wrought-iron or steel tie-bars, as in [Fig. 335], are sometimes used to maintain the line to gauge. They may be made out of bars 3 inches wide by ½ an inch thick,
turned over at the ends to grip the outside flanges. Being made to exact template, they have to be threaded on to the rails before spiking down, and are placed between the sleepers at distances from 7 to 10 feet apart.
Laying Permanent Way.—To preserve a good line and level to the permanent way, it is absolutely necessary that the road-bed should be kept thoroughly drained. If provision be not made for quickly carrying away the rain-water, and if it be allowed to collect under and around the sleepers, the action of the passing trains will work the finer particles of the packing into the consistency of soft mud, which will be gradually squeezed away, leaving the sleepers imperfectly supported and insecure. A loose sleeper involves a depression in the rails, and a corresponding lurch in the vehicles of the train, and a series of these depressions may produce such an oscillation in the train as to cause it to leave the rails.
The height or space from formation-level to rail-level is generally about 1 foot 9 inches for a flange railroad, and about 2 feet for a chair railroad.