The Portland daily press., 1865-07-07
Faday Morning, july 2, 1866.
from the london Morning Post.l
PNEUMATIC RAILWAY UNDER THE
THAMES

.F A++oeA AAit A%lt'ANh morning fOst.l
PNEUMATIC RAILWAY UNDER THE
THAMES. 81
II Is proposed 10 form a pneumatic railway
10 connect the Waterloo station of the Lon
aon and Southwestern Railway with White
han, and which win pass under the Thames
,et"een those points. In the construction of
he railway three piers win be built up below
the bed Of the river by means of iron caissons
gradually lowered into the bed of the river
and exeavated from within in the same man
ner as the piers of New Westminster. Hum
geriord and Blackfriars bridges were made
Nhen these piers have been brought up to the
required height from the foundations, and to
within few feet of the bed of the river the
upper portions Of the iron caissons win be
taken OH, and the earth portions of the bed of
the river between the line of piers will be
dredged down to the level of the upper course
Of masonry of the piers, and in the trouph
thus formed the iron tube, which will form the
pneumatic railway, will be laid.
The tube win be lowered in four separate
sections, and when laid, their ends will be Sc
cured together In very simple and ingenious
manner. The tubes being hollow will. of
course, require to be weighted in order to sink
them, and, when down, they will be kept Sc
curely in ther place by cramps. and viii be
covered with a thick bed of concrete. Il over
these will rapidly be deposited the soil of the
river as 1t is washed down by the scour of the
ude INTO the trench in which the tube will be
buried The internal diameter of the tube
viii be II it., and its area 113 square feet the
external diameter is Is #. in, and area 1S3
square feet. The weight of the tube, the con-
crete, the rails, and permanent way will be
about 10 tons per lineal yard, and each sec
ton Will be lowered in lengths of 240 f.. thus
making the weight of each section 1900 tons
and Of the entire tube of four sections 4S00
tons.
The portion of the line between Whitehall
and up to the river front of the Thames en-
banlment win be built in briclrwork, and on
the Surrey side the line win also be continued
In brick work under College street and Vine
street, close to the Waterloo Station of the
Southwestern Railway, with which it win
communicate by a flight Of steps from the
York road side Of the station. The steepest
gradient throughout viii not he more than
In 80. Passing as II does across the Thames,
II win be necessary to pass beneath the Thames
embaDkment, and il win also pass under the
Metropolitan District Railway, the low level
sewer Of the main drainage, and the subways
which are 70 be constructed In the embank-
ment. In the old atmospheric system the
train OF carriages was propelled by the ordina-
~ pressure OF air acting upon piston moving
In tube, the air before it being more or less
exhausted. a
The tube was, however, laid upon the ground,
and the carriages passed over it In a longitude
nal or continuous valve, opening at the top,
along which rod connecting the piston with
the carriages passed, the valve closing as the
rod moves forward. The area Of this tube was
necessarily small, and the pressure required
to be exerted was proportionable. All at
tempts to prevent waste of power by leakage
were useless, and the attempt has been univer-
sally abandoned, on account of the expense of
working such lines of railway. In the case of
the Pneumatic Railway, the carriages them
selves, and not the small piston, travel through
the tube. The area upon which the atmoS-
phere has to act is at least fifty times greater
than offered by the smaller tube, and, leakage
or waste OF power is practically altogether OBJ
waited.
hecarriages will be like am elongated omni-
bus, having at one end framework of the
same form, and nearly the same dimensions, as
the sectional area of the tunnel The car
riage, with its closely fitting collar, forms, in
fact piston. The power which propels the
piston carriage proceeds from rotary, MAJ
chine, or. "eiector,n concave in surface, and %
feet in diameter. This is made to revolve by
steam engine, at such velocity as may be re-
uuired the pressure of air increasing accord
ing to the greater or less velocity. Nothing
can bemore simple than this mode of accumu-
Iating power. The "ejecter" viii reyolve in an
iron case, something like that of huge paddle
Wueel ABOVE 5FOUltls Dub bileft Is nO CTduh, vi
axle, or shaft to which it gives motion
When driving the air into the tunnel there
rush fresh breezes to the disc to supply the par
tial vacuum caused by the air sent below
ON the other hand, when exhausting the
tunnel, and when the escape valves are OPEN
ed, the air rushes out in a gale or hurricane,
according to the rate at which the disc is moy-
ing When at full speed, stiff gale of wind is
blown. A small am0nnt offorce is sufficient
1sca or,d xuho
ing, itfapidy acctlmulates power, SO much so
that: at the experiment tube in the grounds oI
the Crystal Palace. its own unaided revolu.
Uiuus were sufficient to bring the carriage
through large portion oftunnel. The power
thus obtained is applied in avery simple man
ner. The trains from the Surrey side will be
blown through the tunnel. The return voy-
age win be made by the exhausting process
inst as one would draw water through straw
At signal given by eletcric telegraph, {
valve viii be opened, the doors ofthe iron tub'
thrown back. and the air-sucking discs set in
full swing. Instantly the carriage, which
is at the mouth of the tunnel at the lower end
feels the effect of the air rushing into this sue
ton vault, the external atmosphere acts upor
the carriage from behind, with its ordinary
pressure Of some IA lbs. to the inch, and being
removed of portion of the pressure in front
the carriage will be forced forward on its re-
turn journey. The iron doors at the uppel
station open at the pressure increases, and the
adVahelng carriage emerges into daylight
Ihere Is this important point of difference be
tween the peashooter of our school-days anG
the pneumatic tube, that in the former the
pea or pellet IS projected violently from the
mouth OF the tuDe, while in the latter the ear
rlages gllde gentiy along, gradually slackenine
phere is restored. tslf ef