IMPROVEMENTS IN SIGNALLING ON RAILWAYS, AND IN APPARATUS THEREFOR."
Year: 1876

page_text: PROVISIONAL SPECIFICATION left by Joseph Wilman Wood, William Henry
Shakespear, and William Phillips Thompson at the Office of the Commissioners
of Patents on the 11th August 1876.
JOSEPH WILMAN WOOD, WILLIAM HENRY SHAKESPEAR, and WILLIAM PHILLIPS
THOMPSON, all of Liverpool, in the County of Lancaster. "IMPROVEMENTS IN
SIGNALLING ON RAILWAYS, AND IN APPARATUS THEREFOR."
This Invention relates chiefly to improvements on Specification, No. 3772, of
1875; it consists,―
1st. In an arrangement by which the guard, or preferably driver, can com-
municate with stations or another train on the same line of rails, and receive an
answer whether the trains are in motion or stationary.
Between or to one side of the main rails we place a subsidiary rail or conductor.
The best form perhaps for this rail is a series of gas pipes connected by T bolts
that fasten them down to the posts or sleepers or by elastic connection of any
suitable kind; a soldered wire, for instance, so as to give rigidity, and yet allow for
expansion. If T bolts are used one branch of each T enters one end of a gas pipe;
light T or channel iron would do. On the engine (or guard's van) is a spring
(electrically insulated from the train) with a wheel running on bearings at the end;
or instead of the wheel a metallic brush or scraper in snowy countries or lines little
used; this wheel or scraper runs on the said subsidiary rail or line of gas pipes. In
each signal box or station we place an instrument, which can at will bring the
subsidiary rail (which must be insulated from the main rails) in electric connection
with one pole of a battery, and bring the main rails or either of them in connection
with the other pole.
The same instrument can connect or disconnect an electric bell with the special
rail and main rail, disconnecting it whenever it connects the battery. Similarly a
telegraphic instrument for reading off messages could be connected, and the bell
and battery thrown out of connection. A similar electric bell and battery, or
telegraphic instrument bell and battery is placed on each locomotive or guard's
van; one pole of this battery is in electrical communication with the rails, the other
with the insulated spring, and through it with the subsidiary rail.
If a driver of one locomotive wishes to communicate with another on the same line
of rails, or with a signal box, he connects his battery with the special and main rails
(it need never be disconnected from one of them, provided it is from the other).
Die 2.27

page_text: This causes the circuit to be completed and rings the nearest bell or Dells on
circuit, whether at a station or on another locomotive.
The periods of time during which the bell rings can represent different signals.
Four short periods together might mean "put on the telegraph instrument." The
driver could then send a regular message; similarly a signalman could telegraph to 5
a train. By having the subsidiary line broken at each station a very simplo
automatic or otherwise block signalling system could be established; cach train as it
enters a block would telegraph its approach; if no reply was returned the driver
would know there was danger, if "all clear" was signalled he could go on ahead. A
station-master could not telegraph "all clear" if another train was in the way, as
that would intercept the signal, and would have already received warning, and
could signal danger. If an engine broke down or stopped for any purpose he could
signal the fact to both stations.
2nd. With the train signalling arrangement in the form described in Specification
No. 3772, of 1875, wo frequently find it bost to use a horizontal spiral spring, and
place the disc on a horizontal spindle going through the spring, arranged on two
bearings on a single insulated metallic support on the top of the carriage. The
support will be insulated with a cap of vulcanite projecting downward bell-shaped,
so as to thoroughly shield the part beneath from rain; instead of the guard rail we
use its mechanical equivalent, a small upright flexible blade of spring steel pro-
jecting from the railway carriage top up through the frame of the disk spindle, and
connected with the "ground line," but entirely clear of the aforesaid frame, so that
there is no chance of contact; a second disc on the other end of the disc spindle
comes in contact with this blade whenever the spindle is shot out its full extent
by the opposing force being removed from compressing the mainspring.
As it is found that considerable strength is necessary to pull the cord back
sufficiently to give an alarm in the old way we now usually attach the cord to the
thin flexible blade aforesaid, and a gentle effort pulls it against a pin on the frame
of the disc spindle, and so makes a contact, and completes the circuits or circuit,
for we sometimes work the apparatus with only one battery on the engine, and
none in the van. In this latter case the guard could have a bell or instrument in
his van as before, so that by temporarily completing the circuit in the guard's van,
and breaking and making contact at the engine a message could be forwarded to
him by the engine-driver, to which by reversing the process and working in the
usual manner the guard could reply.
The insulated frames at each end of a carriage have cach two pins, round which
two wires are fixed, and extending across the top of the carriage, and kept apart by
stretching pieces or struts with eyes at each end, the pins carrying the wires are
arranged so that the lamp man or other person getting on the roof can put on a
handle and screw them up tighter, like the pegs on a harp, and then place a pegs in
the holos in said pins to keep them from unwinding. Thus there are only two
insulated points of connection in each carriage, and the whole can be fixed or taken
down in a few minutes, merely requiring being screwed down.
Another advantage is that the frames being free to swivel on the single insulated
support can adjust themselves to the oscillating of the carriages, or to slight
differences in the adjusted heights of the discs on respective carriages.
We find too that it is sometimes advantageous to make the discs flat (or dish shaped)
with a projecting cone in the centre, and a not quite so much projecting rim round
their peripherios, so as to prevent any chance of two discs pushing each other to one
side and sliding past, the cones are then the points of contact, and are prevented
from leaving contact (by any ordinary oscillation of the train) by the rims.
For milk trucks we either fix two posts and a cross piece to place the mechanism
on, or construct a portable conductor composed of a light bamboo and wire witl
metallic caps at each end to fit on to the opposing discs, and thus bridge over the
milk truck.