IMPROVEMENTS IN PONTOONS CHIEFLY APPLICABLE TO CONVEYING RAILWAY TRAINS ACROSS TIDAL AND OTHER RIVERS
Year: 1864

page_text: PROVISIONAL SPECIFICATION left by William Henry Barlow at the Office
of the Commissioners of Patents, with his Petition, on the 11th January
1864.
I, WILLIAM HENRY BARLOW, of No. 19, Great George Street, Westminster,
do hereby declare the nature of the Invention for "IMPROVEMENTS IN PONTOONS
CHIEFLY APPLICABLE TO CONVEYING RAILWAY TRAINS ACROSS TIDAL AND OTHER
RIVERS," to be as follows:-
My Invention consists in constructing pontoons chiefly applicable to conveying
railway trains across tidal and other rivers in such manner as to be capable of
varying the depth at which the pontoon floats in the water, so that the deck
or upper surface can be always brought to the level of the wharves at which
such pontoon would receive or discharge its load. For this purpose I employ
a large deep sided pontoon, of a rectangular or other suitable form, divided
into compartments, and I cause it to float at different levels by allowing water
to run into it or expelling water from it. The means of causing the water to
flow into or out of the pontoon will be hereafter described. The application
of the Invention is more especially directed to conveying railway trains across
tidal or other rivers, and the mode of using the pontoon is as follows:-
The pontoon is floated alongside a suitable wharf, and is then lowered down
until its bottom rests on surfaces provided to receive it, and is so adjusted in
position that rails laid upon its deck are made to coincide with rails upon the
wharf, and when the pontoon is so placed the rails upon its deck form
practically part of the railways upon the wharf, so that engines and trucks may
run over it in the same way as they do upon railway turntables when fixed

page_text: in position. The cargo is then run on board, and when the pontoon has
received its load a sufficient amount of water is expelled to cause it to float.
The pontoon is provided with a steam engine, one of the uses of which is to
propel it through the water to the opposite side of the river where another
wharf is to be made or provided in like manner with rails coinciding
with those upon the pontoon. Several modes may be employed for expelling
the water from the pontoon, but I prefer the following:-Firstly, the
pontoon is to be divided by vertical partitions into three or more air-tight
compartments extending from the top to the bottom of the pontoon. These
compartments must be supplied with water valves at or near the bottom,
and air valves at or near the top. These air pumps of suitable size
would be employed and worked by the engine to pump air into the several
compartments. If the air valves are closed, and the water valves are opened,
it is obvious that as the air is pumped in the water will flow out and the
pontoon will rise in the water. And if the air pumps cease to work and the
air valves are opened the air will flow out and the water will enter at the
bottom and the pontoon will descend in the water to any required level, the air
valves, must then be closed and the pontoon will remain floating at that level.
Also by adjusting the height of water in each compartment the deck of the
pontoon may always be brought horizontal even though there may be consider-
If the air
able inequality in the distribution of the load upon the deck.
valves and water valves are both closed, air being an elastic gas can be pumped
in until a suitable pressure is obtained before opening the valves, this may
be done while the pontoon is resting on its bearings at the wharf, and the air
thus subjected to pressure will become an accumlator of the power of the
engine, so that when the lower valves are opened the water will flow out with
greater velocity than that which would result from the direct action of the
engine. The steam engine would be so arranged as to work the air pumps
and the propelling screws either separately or at the same time as might be
required.