The daily dispatch. [volume] (Richmond [Va.]) 1850-1884, 1857-01-28
THE DAILY DISPATCH.
Wednesday nIorning, Japuary -, 1857.
The Virginia Blue Ridge Tunnels and
Railroad.


Ridge Railroad This road, IL miles in length has
been constructed altogether on State account and
forms that portion Of the line of the virginia
Central Railroad which traverses the Blue Ridge
Beginning at small stream called Mechum's ri.
yer, which winds along the base of the Ridge In
Albemarle county, II ascends the eastern slope oi
the mountain by nearly continuous grade of from
20 to Is feet per mile for about l3 miles, and then
piercing the mountain, traverses its dark recesses
for about 4-5ths of mile more, sill ascending
nth the same inclination, and at length emsrpes
upon the Valley of Virginia at point ], ,464 fec,
above tide water. By descending grade OF
about 3 miles at g.! same inclination, the road
reaches the village of Waynesboro, situated up-
on the banks of South River, branch of the Po-
tomac; whence the road proceeds West under the
charter of the Central Railroad Company. II
would be difficult to point out section of railway
of the same length In the United States of more
interesting character, whether we consider the un.
surpassed beauty of the scenery or the magnitude
OF the work executed. The pen of an Irving
might here find worthy theme in describing the
glorious landscapes continually presented to the
eye, and the pencil of An artist could scarcely fill
his canvass with a greater variety of beauties
than are here displayed. 1t is not however, our
object to extol the beauties of nature, but rather
to give an account of some of the obstacles she
presented, and of the difficulties encountered iu
overcoming them in the prosecution of the four
tunnels and the railway. And of the first magni-
tude among these is the Great Tunnel.
The point selected for the perforation of the
mountain Is known as ''Rockfish Gap" through
which the Staunton and Charlottesville Turnpike
passes. The Blue Ridge is here narrower and
lower than elsewhere for many miles north or
south. The elevation above tide in the Gap itself
is only about 1856 feet, while either side of the
George the mountain rises abruptly to An eieva.
ton Of about ,l20 feet. The George is devious,
but the Tunnel, pursuing q straight line as the
shortest distance from side to side, passes under
one of the highest peaks, although both the en-
frances are in the holiows which head In the Gap
itself. While, therefore, the Tunnel is about four
hundred feet below the summit of the Ridge in the
Gap, its line passes under an elevation nearly
seven hundred feet above its axis. 1t is owing to
this fact that the use of shafts has net been re-
sorted to, a very simple calculation showing that
while these would have been enormously expen-
sive they would scarcely have accelerated the
perfo alton.
ceiye at each end light sufficient for the purposes
required, and the greater elevation of sixty feet
tho Western than the Eastern entrance will create
draft of air that will suffice for ventilation. The
length of the Tunnel is 4,273 feet and, as before
stated it ascends from East to West at the rate of
seventy feet to the mile. AS the question has been
frequently asked why it was not made level with
slight inclination from the centre in each direc-
tion, it may be as well to give the reasons which
induced the Engineer to construct it as it is The
valley on the Western side of the mountain Is
much higher than on the Eastern. The Tunnel
emerges just at the head of this valley, where the
mountain rises abruptly from it. Itfollows, there
FORE that if this end of the Tunnel were lowered
to level with the Eastern, the length of the Tun-
mel would be greatly increased, as the inclination
of the valley is comparatively gentle, and the Tun
mel below it's surface but slowly diminished; this
increase of length would be probably at a rate of
ten to fifteen feet, for each foot lowered. This end
OF the Tunnel was considered therefore, as fixed
point, and the ueston remained rs to raising the
Eastern end Iu order to do this, the grade, which,
as before stated, is nearly continuous from Me-
chum's river, would have been increased to rate
of more than eighty feet to the mile, the additional
expense of working which for an indefinite period
of time it was considered would exceed the tempo.
rary expense incurredsin pumping the water from
the Western end Of the Tunnel while in process of
construction. The above reasoning shows plainly
the correctness of the plan adopted, viz: to make
the Western end of the great Tunnel tho summit
of the grade and to make this grade as nearly cons
tinuous possible, to the base of the mountain,
which may be considered as commencing at Me-
chum's river. The survey of the road was begun
iu May, 1649; the summer and fall CT which year
were consumed in the location and preparation of
the work, and in contracting for its execution.
delay of some months was caused by the failure of
the person to whom the excavation of the Tunnel
was first let, to comply with the terms of his
tract thus making it nece ssary to relet IT, that
the excavation of the cuttings which form the ap-
proacbes to the tunnel on either side was orfair-
iy begun until the month of March, 1850 Each of
these cuts was carried to depth of sixty feet
through the hardest rock, their aggregat length
being nearly s0O feet. The work of excava;ing
them proceeded steadily from this time forward -
The perforation Of the tunnel itself, was begun
the Western side in August, 1850, and on the Eas
tern side in January, 1851. The headings met on
the 29th December, 1856, six years having been
occupied in driving the Eastern, and six years and
Ave months in driving the Western heading. The
length of heading driven from East to West, was
g ia feet, and from West to East 3 l34, the total
length being 24S feet The average rate Of per-
foration of the heading has been, therefore, on the
Western side 332i feet per year,27a feet permonth,
little more than one foot per working day OF
"a hours, and on the Eastern side 352l feet per
annum; 295 per month, or about II feet per work.
ing day of "a hours.
Owing to the batter or inclination of the face
OF the cuts at the end CT the Tunnel, the length
measured along The floor exceeds that along The
root, being 1878 feet. Again the masonry of the
portal at the Western end projects ii feet into
the open cut, SO that the actual length from end
to end of the Tunnel as finished, Is 1924 feet -
The entire excavation will most probably be
completed by the lst of June, 1857, when the
whole time consumed upon it, from the COM
meme emsnt of the perforaiion, will have been ve-
~ nearly seven years, giving an average rate of
p,r oration CT 81 feet per month. The shape of
the cross section of the Tunnel is elepical-iis
greatest width in the clear 16 feet-and height 81
feet When arching was found necessary, as was
the case for 700 feet, the dimensions of the exca
vation were increased, so as to admit of the
thickness CT the arch which is in some places as
much as feet. The number of cubic yards ex-
cavated, has been computed to be so 000 or about
III per linear foot. The number of brick used
In arching, Il00.C00, and the number of GU
bic yards Of stone masonry $50 The cost of the
Tunnel. when completed, may be taken at $464,
0O0-$24 coo cf which sum has been expended for
masonry. This gives for the whole a rate of
$lOS 80 per linear feet, and includes all charges
The cost of that portion which is unarched, is
about $98 per .ft.. and of that which is arched
about $l6l per l # The cost cf excavation, per
cubic yard, Including the expense Of ventilation
and Of pumping is about Sc so, aud that of exca-
walton. exclusively, about S6 So The rock en-.
countered Is blue slate, trap and quartz, all ex.
ceedingly hard and difficult to blast. Although
this has been the cause of slow progress in per,
fora.ion it gives this work, nevertheless, In .
points, q great advantage over most Others Of The
kind, for the roof is by Nature 80 perfectly firm
and secure with the exception of two lengths OF
500 and 200 feet, near the Western end, which
are arched that the great cost Of archng for five.
sixths of Its length, is avoided Air has been sup
piled and water discharged by means of chain
pumps. worked by horse power. The quantity Of
water thus discharged at the Western end, has
been sometimes as great - ninety hbds per
hour.
There have been but two accidents during the
progrsss Of this work, both caused by premature
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