IMPROVEMENTS IN CROSSINGS FOR RAILWAYS, AND IN MACHINERY OR APPA- RATUS FOR WORKING AND LOCKING RAILWAY POINTS AND CROSSINGS
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by Joseph Potts at the Office
of the Commissioners of Patents, with his Petition, on the 30th
September 1873.
I, JOSEPH POTTS, the younger, of Sunderland, in the County of
Durham, Architect, do hereby declare the nature of my said Invention
for "IMPROVEMENTS IN CROSSINGS FOR RAILWAYS, AND IN MACHINERY OR APPA-
RATUS FOR WORKING AND LOCKING RAILWAY POINTS AND CROSSINGS," to be as
follows:-
This Invention consists in the simultaneous working of the points
and crossings on railways, and in the locking of the same, the metals
of the main line being moreover continuous and free from gaps or
breaks of any kind when the points are closed and locked, and the
metals of the branch or siding in connection therewith being also
perfectly continuous and free from gaps or breaks of any kind when
the points are open and locked for shunting. I thus prevent the
dangerous vibrations and oscillations or shocks at present experienced
in railway trains and rolling stock while in the act of passing over
the points and crossings now generally used, and more especially when
the trains and rolling stock are travelling at high rates of specd, whilst
I further insure perfect safety even in the case of facing points.

page_text: the moveable rails also sets the swing block to the crossing rail of the
branch or siding.
In lieu of a swing block I may use a sliding block or plate having fixed
thereon two short lengths of rail, the one length being parallel to the
crossing rail of the branch or siding, and the other parallel to the rail
of the main line. This sliding block is moved by horizontal bell cranks
and links, or connecting rods worked from the main connecting rod and
moveable rails, as herein-before described, or by any equivalent arrange-
ment of mechanism.
I further propose an arrangement as an adjunct to the above whereby
the action of the pointsman's handle or lever used for opening or closing
the points or switch raises (whether the same be open or closed) a block
pin slotted into the bed plate of the fixed portions of rails opposite to
the points, and a corresponding block pin slotted into the bed plate of
the rail opposite to the swing or sliding block, the effect of which is to
lock both the said points and swing or sliding block so that it shall be
perfectly impracticable to alter or move either the said points or swing
or sliding block while a train is in progress on the main line, or in
process of being shunted without the action of the said handle or lever
of the pointsman.
The same operation of the lever works by suitable connections well
understood the distance signal which shews to an approaching train
the position of the points, and whether the main line is locked open, or
otherwise.
I furthur propose, by the aid of springs or counterweights, to keep
the point lever in the position for locking open the main line, so that
such lever would not remain at any intermediate position, but would
only be fixed in the position for locking open the branch or siding by
the usual spring catch. Or if preferred the spring catch might be
dispensed with, in which case shunting could only be effected by the
pointsman continuously depressing the lever while the operation was
going on, after which the pointsman would release the lever, which
would return at once by the force of the spring or counterweight to the
position for locking open the main line.
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