TRANSACTIONS OF THE SECTIONS. 229 
was laid before the Section for the purpose of showing that guide-walls, if not too 
high, can be constructed with small stones in a cheap and effective way to direct 
the currents, and maintain a channel at a considerable distance from the shore in 
bays and estuaries, 
A new Construction for finding the Vertical Shearing-stress and the point of 
greatest Bending-moment in a Beam loaded in any way. By JouNn 
Nevittet, C.2., M.R.I.A. 
The vertical shearing-stress of a beam at any point is known to be equal to the 
weight on the next pier less the weight lying between this pier and the point. It 
is generally represented, graphically, by ordinates to the beam of one side only. 
Now as the sum of these stresses must be zero, those on one side being positive 
and those on the other negative, the proper graphical representation is to show 
them according to their signs above and below the beam, positive and negative as 
they exist. This leads to a simple geometrical construction for finding the shearing- 
stress on a beam loaded in any way with a number of weights. Find the line of 
shearing-stress for the beam itself; then using ¢hzs line plot on it the line of shearing- 
stress for the first weight, distributed or single, but making the ordinates vertical 
to the beam itself. Plot from this second shearing-line a third shearing-line for 
the third weight, and so on. The shearing-line last found gives the shearing-stress 
of the beam arising from all the weights, including that of the beam. The con- 
struction gives the lines of shearing-stress for each point of the beam at each step 
also. 
~ Where the shearing-stress is a maximum, the bending-moment is zero; and 
where the shearing-stress is zero, the bending-moment is a maximum. Conse- 
quently where the line of shearing-stress, as here constructed, cuts the beam, the 
point of intersection is that of the greatest bending-moment. 
The areas formed between the line of beam and the lines of shearing-stress, 
above and below, are always equal. 
Improved Patent Saddle-rail and Railway Permanent-way Construction. 
By W. Seaton. 
The author first explained his original saddle-rail, which had been in satisfactory 
use upon various railways throughout the country, including the Great Western 
Railway, where for fifteen years uninterruptedly it had continued in use. On the 
aia Railway it had been laid and maintained with great economy. 
he improvements now made consisted of rolling the saddle-rail with flanches 
and introducing transverse sleepers under the longitudinals, and bolting the rails 
by the flanches vertically through the longitudinal bearers’ and the transverse 
sleepers, thus combining the whole together in a firm framework-like structure 
without any understrain upon or injury to the bolts or fastenings—the intro- 
duction of transverse sleepers under the longitudinals giving a much wider base to 
the road and a much stronger vertical and lateral resistance to rolling loads worked 
at high speeds, with a great reduction and cost of materials and economy of first 
cost for construction and maintenance of the permanent way. 
On the Prevention of Railway Accidents and Automatically Recording the 
Movements of the Points and Signals and other Apparatus of Railways. 
By W. Suita, C.Z. 7 : 
The author prepared this paper as supplementing that portion of the President's 
address read before the Section at its opening in which he gave a brief sketch of 
the improvements that had recently been effected in the working of railway-traffic, 
and wherein he shortly described the “ block system,” the signalling arrangements, 
and the “interlocking of the points and signals by mechanical means,” so that a 
mechanical check was set upon the signalman, who could not pull over certain of 
the point- and signal-levers until certain others were first put right, and whereby 
every thing was moved and worked according to a prearranged system. 
