LIGHT RAILWAYS FOR NEW SOUTH WALES. 253 
ever was not how a cheap line could be made. A line laid along 
a main road must have its surface even with the road and a trench 
had then to be cut to let in the ballast, sleepers, and rails, and in 
_order to preserve the track in good order for the rolling stock and 
still allow other wheeled traffic to pass over it, a guard had to be 
fixed to each rail, and the ballast had to be brought up to the 
level of the surface of the road, so that the cost of this kind of 
line was increased by having more costly formation, additional 
steel in guard rail and additional material and labour in its assorted 
ballast for the top surface. When completed this kind of railway 
seldom had good grades, as it had to adhere to those which hap- 
pened to exist on the roads, which were very likely to be bad ones. 
The maintenance of such a line was always very costly, for unless 
the rest of the road was metalled and keptin very excellent repair 
all the wheel traffic would be attracted towards the tramway on 
account of the good surface, and the wear and tear would be 
enormous. As the grades were those of ordinary roads, traffic 
expenses would be high because the loads would be small. It was 
clear therefore that it would generally be better to go off the road 
to find a location for a light railway. The cheapness of sucha 
line must necessarily depend upon the possibility of following the 
surface with easy grades and curves of not excessively sharp radii. 
Ifeasy grades could not be obtained without running into cut- 
tings, there would not be much cheapness about it. If the sixty 
pound rails were adopted as the minimum, then it would be in 
any case undesirable to use steeper gradients than one in sixty. 
This was the ruling gradient on the Molong, Parkes, and Forbes 
line. It was only obtained there with some difficulty. Curves of 
ten chains radius might be taken as comparatively unobjectionable. 
This was the radius of many of the curves on the Milson’s Point 
extension railway, and was there adopted in order that the 
requisite distance to give as flat a gradient as one in fifty, might 
be obtained. As regards number and kind of sleepers, it was 
undesirable to put them wide apart, the spacing produced by 
putting eleven sleepers to the ten yard sixty pounds rail gave a 
very good result, 
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