for rail-joints are likewise used to make a strong-er union (fil. 25, 3). These have flanges which extend down over the foot of the rails and bear upon the cross-ties (fic. 9),to which they are spiked. Fig ures TO TO 12 show various rail- and joint-sections used upon American railroads.
allow for their expansion and contraction by changes of temperature, the rails are invariably laid with a slight space between them. The common rule in this respect on American railways is to allow 4-5,1 of an inch space in winter and -116- of an inch in sunnner. The boles in the fish- and angle-plates are for this reason made oval, to allow for the end movement of the rails. The shoulders of the bolts, immedi ately under the heads, are likewise given a corresponding oval section, to conform to the shape of the hole in the-fish- or angle-plates into which they fit. By this expedient the bolt is prevented from tuniing when the nut is screwed on.
Nut-/ocks.—Much difficulty is experienced in keeping in place the nuts, which the almost continuous vibration the rail is subjected to by the pas sage of trains tends to loosen. To guard against this, many forms of nut locks have been designed. A favorite artifice to meet the difficulty is that of rolling the fish- or angle-plates with a longitudinal groove about 3,g of an inch deep along their entire length. This groove is jnst wide enough to receive the bead of the nut, and is intended to prevent the nut from unscrewing.
other forms of joint have been proposed, and to some extent introduced in practice. The Fisher " bridge-joint " 25, fig. 5), au American invention, is one that has met with favor. In con tradistinction to the fish- and angle-plate joints, which apply the support under the head of the rail, the Fisher joint applies it under the base. From Trautwine's description, it consists of a flanged iron beam about 6 inches wide and 2 2 inches long, which extends across and is spiked to the two joint-ties. The two rail-ends forming the joint rest upon this beam and meet at the middle of its length, and are held down to it by a single U-shaped bolt with a nut on each leg. The corners of the rail-flanges have rounded notches, through which the bolt passes, and a wedge-shaped piece with a hole, through which the shank of the bolt passes, is placed over this and rests upon the rail-flanges, giving a level bearing for the nut.
This form of joint does not require the sharp undercut head that is neces sary where the fish-plate fastening is used, so that its adoption permits of the employment of the stronger pear-shaped rail-bead. Ftirthermore, it obviates the necessity of drilling or punching. the web of the rail.
SupporIca' ana' Sztspendea' as to whether the joint rests directly upon a cross-tie (fii. 24, fig. 17) or is placed between two ties (fig. IS), the terms " supported joint " and "suspended joint " are used respectively to distinguish them. The suspended joint is in vogue npon the majority of roads, experience having shown that this disposition affords ample strength and less liability to injury of the rail-ends. For securing the rail to the cross-tie, hook-beaded spikes (fig. 17) are commonly used. These are driven in alongside the foot of the rail and on both sides in such a manner that the booked bead of the spike overlaps and grasps the base of the rail. The supported joint was formerly very generally used in con nection with chairs of wrought iron of various patterns. A simple plate of wrong-ht iron drilled or punched with holes for the admission of the spikes is still used in Germany to some extent.
Inzporlance of Cona'ition of Road-bcd and Track.—Upon the condition of the superstructure of the road-bed and its maintenance in the most excellent condition will depend in large measure not only freedom from accidents, but also the railroad company's ability to conduct its traffic with economy and despatch. The price of safety is eternal vigilance, and the continued good condition of the road-bed and track can be assured only by some well-devised system .of daily inspection and constant repair. The proper management of this important branch of the service is effected by the division and subdivision of the road into sections and sub-sections, to each of which there is assigned a well-organized body of trained officials and subordinates, who are responsible for the condition of the section placed in their care.