XXVI. ABSTRACT OF PROCEEDINGS. 



wheels, there being no purchase or bite, to enable the power 

 applied to take effect. This is counteracted by sanding the rail, 

 thus increasing the angle of friction, but this has its limit, and 

 when the traction due to the load, enhanced by gravity on a very 

 steep grade, is excessive, the purchase on the road by the wheel 

 must be obtained by some device in the nature of a rack and 

 pinion. After some early attempts, the rack and pinion system 

 invented by Abt, seems to have found the most favour, and about 

 one hundred rack lines on this and other systems in various parts 

 of the world, including some of the Australian Colonies, have 

 been successfully worked. 



The author then proceeded to describe the Abt construction as 

 generally consisting of two or more rack bars, laid centrally and 

 vertically between the ordinary bearing rails, the rack being 

 engaged with corresponding pinions driven by special cylinders 

 inside the engine, the ordinary adhesion driving wheels being 

 actuated by separate outside cylinders. The advantage of dupli- 

 cating or triplicating the rack bars, being not only to give increased 

 purchase, but to furnish a reserve of holding power in the event 

 of one set breaking. The Nilgiri Hills, metre gauge, rack railway 

 in India, was then described as well as the engines in use, and 

 their performances; also the permanent way and rack for standard 

 gauge with three rack bars, which had been suggested by the Abt 

 Company for a steep incline now under survey in this colony. 

 Some other lines were referred to, more or less fully, and also the 

 Staub rack system, which differs from the Abt, and which, for 

 special reasons given, has been adopted for the Jungfrau electric 

 rack line, in Switzerland. 



The grades dealt with by the rack seldom exceed that of the 

 Jungfrau, which is I in 4, though there is a 1 in 2 line also in 

 Switzerland, on what is called the Lochar system, which was 

 described. Except in special instances of light passenger traffic, 

 1 in 12J should not be generally exceeded, this grade being the 

 steepest which could be surmounted by an ordinary adhesion 

 engine, with no load behind it, hence any steeper grade would 



