LXII. DISCUSSION. 
might go on for a considerable time, to the detriment of the roll- 
ing stock and the discomfort of the passengers. 
The ideally perfect curve would be one in which the centrifugal 
tendency would be met by a uniform rise in the outer rail from 
the springing to its maximum at the centre of the curve, and a 
similar fall to the end. The minimum of oscillation above the 
springs would then occur, there would only be the gentle rise and 
fall in the whole vehicle due to the flat gradients of the outer rail. 
This would only be completely gained by lengthing the transi- 
tions so that they should meet, absorbing the circular curve 
altogether, and though this would be probably impracticable in 
very long curves, the ideal ought to be approached as nearly as 
possible in high speed lines. Complete parabolic curves were in 
use on the little two feet gauge Festinndég lines, on the extension 
of which he had been employed, and though the great lateral over- 
hang of the rolling stock, due to the narrow gauge, promoted 
oscillation, and the curves were exceptionally sharp, and the speeds 
high, he never travelled on a smoother line. 
The present paper referred to small tramway curves, but what 
he had said would, to a large extent, apply to these, because though 
the speed was much less on tramways than on railways, the curves 
on the other hand were much sharper. 
Mr. P. W. Suaw said the necessity of easement or transition 
curves, on both railways and tramways, had been more fully 
recognised by engineers in recent than in former years, when they 
were left to be put in by the platelayers, and came to be known 
as “platelayer’s curves,” which curves may be all very well for 
large radii, but when dealing with small ones, something more 
definite is required to minimise the shock on the rolling stock, 
and there can be little doubt but that the cubic parabola will be 
found to answer that purpose in most cases to the fullest extent. 
He was sure the excellent papers the author had communicated 
to this erviseced on a —— would be the means of bringing 
that particular luse. On tramways, where 
