90 



C. O. BURGE. 



by the Abt Company in the case of the 1 in 12| grade here. This 

 is required to prevent the tendency to mount the rack, and for 

 the same reason, it is evidently necessary that the relative levels 

 of the ordinary bearing rails and of the rack should be rigidly 

 preserved. With this view, steel sleepers have been advocated, 

 and have been adopted in the Jungfrau line, so that a more rigid 

 framework is attained, than if the fastenings were to ordinary 

 wooden sleepers. But when the sleepers are of hard wood, such 

 as in the Nilgiri case, and in Australia, the framing would appear 

 to be sufficiently rigid with the timber foundation. It need hardly 

 be stated that in either case, the road must be well ballasted, and 

 maintained in the best order. 



Points and crossings might generally be avoided on a rack 

 portion, and limited to stopping places and junctions where easy 

 adhesion grades for other reasons might be interposed. I find 

 however that in the case of the Nilgiri line already referred to, 

 the consulting engineer has ordered the short gaps in the rack at 

 easier portions, including stations, as first constructed, to be filled 

 up with the rack, making it continuous, so as to leave as few 

 re-entering places as possible. 



When points and crossings cannot be avoided on the rack itself, 

 the point is made in the same form that we are familiar with in 

 a contractor's temporary road, that is that the two meeting sets of 

 rack bars stop one length short of the actual junction, and the 

 interval is filled in with a moveable rack bar hinged horizontally 

 at the junction end, and adjustable by switch rods at the other, 

 to either line. 



The two rack crossings required, when each set of rack crosses 

 the bearing rail are so arranged that at these places the rack bars 

 and bearing rail are made of the same length, and interlocked so 

 that the same action which moves the rack points described above, 

 causes the rail at one crossing to be moved aside and replaced by 

 the equivalent length of rack, and the rack at the other crossing 

 to be replaced by the rail. 



The braking on rack lines must necessarily be of a very powerful 

 and trustworthy character, and in the steeper grades must be 



