The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1888-04-19
A MONSTER RAILROAD BRIDGE.
The Great Bridge Over the Firth of Forth IL
Course of Construction.

A MONSTER RAILROAD BRIDGE.
The Great Bridge Over the Firth of Forth In
Course of Construction.
New York Press.
When the world was struck dumb with horror
one winter night. ten years ago. at the news OF
the terrible accident to tho Tay bridge az
Dundee, Scotland, it was also astounded az the
magnitude of the enterprise which had caused
the construction of that huge product OF en-
g1neering skill and at the daring defiance which
induced the proprietors instantly to set about
its complete re-erection. This has now been
done. and the bridge. which from end to end IS
10, 500 feet in length and consists of eighty hve
spans ranging from so to PAS feet in length each,
is In daily use. carrying trains of every de-
scription from south TO north Britain.
Presently, however. the world is to be aston
,shed at feat of still greater engineering skllI
In the completion of the monster roadway over
the Firth OF Forth az Queensferry, about eight
miles west of Leith where q rocky promontory
on the north side of the river narrows the dis
tance across to about mile. rocky island call
ed Inch CARVE dividing the deep water space
into two channels of nearly equal width. and OF
the great depth of about 200 feet.
The total length of this great structure, with
out including approaches, will be S,296 feet, or
nearly one and fve-eiehths mile. It lies nearly
due north and south. and comprises fifteen
girder spans of 16S feet resting on masonry
piers. These form the approaches to the nasin
structure. which crosses the Intervening space
of more than mile by TWO spans or LILO feet
each. and two OF $50 feet Ii 10 composed or
cantiievers. and two central Orders OF ordinary
type, each $50 feet in length. which complete
this connection between the cantilevers.
Ibis enormous bridge is being constructed by
the associated enterprise of the North British,
Great Northern, Midland and Northeastern
railway companies, which have for long time
experienced mauT disadvantages from the ex-
listing route between Edinburgh and Perth, at
which former city all their exchange traffic
with the northern Scottish companies converges.
The present route is not only very crcuisous. in
volvine a detour to the west of over twenty
miles, but more than half of it is owned by
rival company, which charges heavy toll for
the use of it's lines In order to obviate these
evils the companies above mentioned have de-
termined on bridging the river Forth with
structure which, when finished, will rank the
greatest engineering work as yet carried out by
human skill
The bridge was designed on the ..cantilever
and central girder SYSTEM" by Sir John Fowler
and Mr.. b. Baker, and was begun in 1883 This
scientific adoption of an ancient type of con-
struction has met with strong approval Of dis
tinguished engineers in all countries and al
ready several important bridges in India and
the United States being carried out on the
same principle.
With the exception of the rolling of the plates
and bars, the whole OF the manufacture and fit
ting is carried at the site of the bridge,
whore fifty acres of land are occupied by shops
and yards. The number of men employed is
tain about 81, 600 tons of Siemens-Marten
steel, which is obtained from works at Glasgow
and Landore. The ultimate tensile strength is
to be from thirty to thirty-seveu tons TO the
square inch, while the greatest strain the struct-
will have to sustain from dead weight,
live loads and wind will never exceed ore fifth
of that amount.
The resident engineer is Mr.. Frederick E.
Cooper, one of the abiest men in Great Britain.
There are times when it is found necessary to
press the work to the utmost under which cir
cumstances the shops and yards are kept open
and busy night and day without intermission.
Up to the present writing the masonry and ap-
proach viaducts have practically been compiet-
ed, some AZ, 900 tons of steel have been manu-
featured of which %, 600 tons have been erected.
The magnitude of the structure and the i'm
possibility of obtaining supports from below
when over the water invite special reference to
the method of erection. The central towers
have been built by means of platforms raised
intervals by hydraulic rams placed inside the
main tubes. These towers are composed of
four tubes piers OF solid rubble masonry
faeedewith granite. twelve feet IN diameter, and
carried up 70 361 feet above high water. They
are strongly Draced and connected on all sides
either by tubes varying in diameter from twelve
to seven feet, or by massive steel eirders of
quadrangular form.
The top and bottom members of the can't
levers erected by cranes of special construc-
tion supported on them, and advanced az the
WORK is executed, temporary ties and columns
being used when required to support and adjust
them IN their true positions. Each cantilever
consists of a top and bottom member and YER
teal and horizontal bracing The top mem bers
TWO in number, thirty-three feet apart from
center to center, each is Quadrangular clrder
braced vertically by six pairs of tubes of clip
tical form as struts, and six pairs of quadrangle
lar ties, varying in length from $50 feet to
seventy feet aud from eight feet to three feet in
diameter. The struts and bottom members.
about 700 feet in length, are strongly braced
against horizontal stresses by quadrangular
Orders of cofrespo nding size and strength.
The railroad track, straight and level through
out, is carried the upper surface of tho
Orders of the approach viaducts, and on the
lower members of the central Orders and CAN'T
levers.
The total cost of this huge piece of work is
estimated at f2, 500, 900 English, or about $l2,-
800. 900.
A list of some of the largest railroad bridges
in the world may fttiugly close this short ac-
count of the great Forth viaduct The Tay
bridge has already been mentioned. Next in
length comes the Moerdyk bridge in Holland,
s. 529 feet in length, including approaches Then
the ,Alexandrowski bridge over the river Volga,
near Syrian, 4, 81 feet. including abutments,
built at total cost of 3d. 675, 900 and weighing
$500 tons. Next comes the road and railway
bridge over the Dnieper at Jekaterinosay. 4. 557
feet in total length, the total cost of which was
SO. ATS, 600; the railroad viaduct over the river
Severn, A. 162 feet long, consisting of four spans
and swing 1877 feet in length. The Louisville
and New Albany bridge over the Ohio comes
next. It is g 453 feet in length 40 feet wide, 95
above ordinary water level and consists of
seven spans two of which are cantilevers and
one swing. The St. Louis bridge, road aud
railway, is 1884 feet long, including approaches;
it is 81 feet wide between the parapets, has
three spans and cost So 727, $50 Another large
bridge with mention of which this notice will
conclude is the Cincinnati Southern Railroad
bridge over the Ohio. It is ], 500 feet in length
its total weight is 2, 179 tons, and the cost of
constructing it was $729, $50.
Scotch Cakes.