The Somerset press. [volume] (Somerset, Ohio) 1873-1977, 1873-12-26
Tire Pneumatic pesnateh.

has an article which gives an account Of
the origin and deVoloPuent7 Of the
pneumatic despatch system in England,
and then goes on to describe the great
pneumatic despatch tube in the heart
of London II says;
The pneumatic tube extends from the
London and Northwestern Railway sta-
tion at Euston Square 70 the Gen
eral ;Postofice in St. Martina le-
Grand. The general station is in Hoi-
born, where is also tthe machinery for
efiectine the transit Of the trains. Here
the tube is divided, so that in effect
there are two tube opening into the sta
ton, one from Euston To Hoiborn, and
the other from the Postoffice. The
length of the tube between Holborn and
Euston is 5000 yards, or exactly mile
and three-quarters, a greater length than
was originally contemplated, but which
was rendered necessary by the avoidance
of certain property on the route. The
tube is Of a hattened horseshoe section
5 feet wide and 4 feet inches high at
the centre, havinga sectional ares Of n
square feet. The straight portions Of
the line are formed Of continuous cast
iron tube, the curved lengths being con'
structed in brickwork, with a fac
ing of cement. The gradient are easy;
the two chief are in As and / In 90,
some portions Of the line being on tho
level. The sharpest curve il that near
the Holborn station, which ia 70 feet
radius. The tube between Holborn and
the Postofiee is ,65S yards in length, OF
1o2 yards less than mile, and ia OF the
same section and similarly constructed
to the first length. Two gradients Of
in Is occur to the Postofice section, but
this steep inclination is in no way inim-
icaI to the working Of the system. The
Holborn station Is situated at right am
giles to the line Of the tubes, which are,
therefore, turned towards the station, in
to which each opens. All through trains,
therefore, have to reverea there, and this
is effected in a very simple manner by .
seIf-acting arrangement. A train, upoa
it's arrival, runs by virtue Of is acquir-
ed momentum up short incline, At tha
summit of which it nomentarily stops,
and then quickly dsscends BY gravity.
In its descent it is turned on to pair Of
rails leading to the other tube, into
which it enters and through which Il
continues its journey, the whole process
Of reversing occupying barely thirty
; seconds. Trains containing goods for
the Holborn station are simply run down
from the top Of the incline on to a sid
ing.
The wagons, or carriers, as they ara
: termed, weigh twenty-five hundred
: weight, are 10 feet 4 inches in length,
2 and and have a transverse contour con
{ forming to that Of the tube. They are
e however, of slightly smaller area than
!. the tube itself, the dillerence-about an
e inch all round-being occupied by q
: nange Of IndiasrubbeF, which causes
|. the carrier to fit the tube exactly, nna
= SO TO form a piston upon which the ais
= acts. The machinery for propeliing the
d carrier consists Of a steam engine having
e a pair Of 24-inch cylinders with 2O-inehb
r stroke. This engine drives fan ~ fees
g 6 inches in diameter, and the t-so aFe
It geared together in such iaapner
4 that one revolution Of the former gives
e two OF the latter, or, in technical terms
n the engine is geared At swo to on'
n with the fan. The trains are drawn
ie from Euston and the postofficc BY e.
d haustlon, and are propelled 70 those
ls points by pressure. The working of th'
p fan, however, is not reversed to sniI
these constantly varying conditions; Al
works continuously, the alternate actor
II of pressure and exhaustion being gov
erned. by valves. The engine take
steam from three Cornish boilers, each
= thirty feet long and six inches in diams
: : ter. Telegraphic signalling Is earFief
= on between the three stations by mean
Of needle instruments.
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