HAR P E R'S
NEW MONTHLY MAGAZINE.
No. CCLIV.JULY, 1871.VOL. XLIII.
THE MOUNT CENIS RAILWAY AND TUNNEL.
ON the morning
following Christmas-day, 1870, a telegram was received in London
from the very heart of the Alps; thence it was dispatched across
the Atlantic, and in the gray dawn of the next day, December 27,
we read it at our breakfast-tables in New York. This dispatch
of just forty-three words read thus:
"The working parties in the opposite headings
of the Mount Cenis Tunnel are within hearing distance of each
other. Greetings and hurrahs were exchanged through the dividing
width of rock for the first time at a quarter past four o'clock
on Christmas afternoon."
This brief dispatch, almost overlooked among the more exciting
ones relating to the war-for the opening of the bombardment of
Paris was hourly expectedconveyed tidings of the practical
completion of the most enduring work ever accomplished by human
bands. The Pyramids will, in time, crumble to dust; but nothing
less than some convulsion that shall shatter the Alps from summit
to base will destroy the Mount Cenis Tunnel.
Perhaps the point of view from which this Alpine tunnel is
of most commercial importance is that it shortens the distancemeasured
by the time required to traverse it, rather than by the space
passed overbetween Western Europe and India. This will appear
from a glance at the accompanying map. At present mails and passengers
by the overland route from London to India proceedby way
of Calais and Lyonsto Marseilles, where they embark, and,
after passing through the stormy Gulf of Lyons, rounding the toe
of the Italian boot and the island of Sicily, reach Alexandria,
or, more recently, the mouth of the Suez Canal, in Egypt; whence,
descending the Red Sea, they cross the Arabian Gulf, and land
at Bombay; or, rounding the peninsula of Hindostan, they enter
the Bay of Bengal, and are disembarked at Madras or Calcutta.
The entire distance from London to Alexandria, by way of Marseilles,
is 2534 miles, of which 833 are traveled by land and 1701 by water,
the whole journey occupying seven or eight days. Ten or twelve
miles an hour is a fair rate for ocean steamers, whereas forty
miles an hour is usually made by express trains on a railway.
If, therefore, any considerable part of the 1701 miles of sea
voyage between London and Alexandria can be performed by railway,
there will be much saving in time.
Now, again looking at our map, it will be seen that, starting
from near the head of the Gulf of Genoa, the boot-like peninsula
of Italy stretches for 600 miles from northwest to southeast,
pointing directly to the coast of Egypt. It forms a natural bridge
half-way across the Mediterranean, in the direct route from London
to Alexandria. Close by the southeastern verge of Italyalmost
at the heel of the bootis Brindisi, the ancient Brundisium,
of which all readers of Horace know something; for the Iter
ad Brundisium ("Trip to Brindisi") is one of the
cleverest poems of the old Roman good-fellow. Any one who desires
to post himself up about Brindisi, from the time when Ennius,
almost forgotten when Horace lived, punningly presents it as pulchro
proecinctum proepete portu ("properly placed with a pretty
port"), and how Caesar put Pompey out of this pretty port,
can find it all told in his Anthon. Here, also, was the terminus
of the famous Appian Way, the spot being to this day marked by
two pillars, one sadly dilapidated. Virgil had here a country
house, the ruins of which are yet shown; and there axe not wanting
those who put faith in their authenticity.
Some day, as a glance at any fair map will show, there will
be two good routes from Europe to India: the one mainly by railway
on land; the other a considerable part by water. The former, leaving
England at Dover, and crossing the English Channel to Calais or
Brussels, will traverse Belgium, Germany, Austria, and what is
now known as Turkey in Europe, reaching the Bosphorus not far
from Constantinople. Thus far the route runs entirely overland,
avoiding the Mediterranean and its long gulfs, and also skirting
the Alps on their northern face. The trains, without breaking
up, will be ferried across the Bosphorus (more properly Bosporus,
"a strait over which an ox can swim," the exact Greek
for our "Ox-ford"), Thence crossing Asia Minor, or,
as we now call it, Turkey in Asia, the railway will round the
southern end of the Caspian Sea, passing through Persia and Afghanistan
to the Indus. Thence running across the head of the peninsula
of Hindostan, it will reach Calcutta. This route, after leaving
the Bosphorus, is, as far as the Indus, just that followed by
Alexander the Great in his famous expedition to Indiaby
far the most, remarkable military march ever performed. The second
route, branching off at the crossing of the Bosphorus, will follow
the eastern shore of the Mediterranean to Syria; thence, crossing
the Lebanon range, it will strike the valley of the Euphrates,
which it will follow to the head of the Persian Gulf, down which
it will descend by steamer, crossing the head of the Arabian Sea
to the mouth of the Indus, where it will again strike the railroad
route across the Indian peninsula to Calcutta. This second route,
from the mouth of the Indus to the upper waters of the Euphrates,
is the one followed by Alexander on his return from India. The
great Macedonian, more than two thousand years ago, showed the
two ways from Europe to India.* But these routes will not practically
exist until the long-vexed, and still to be vexed, Eastern question
gets itself somehow settled. For the present, and for another
generation, we must consider the overland route to India as running
through Italy. And to this route the Alps interpose a barrier
which will be, in a measure, overcome by the Mount Cenis Tunnel.
* Any ordinary map of Southern Asia will show
with tolerable accuracy the two Indian routes of Alexander, followed
by him on his advance and return. The main points to be observed
are: for the overland route, the Bosphorus, the southern end of
the Caspian Sea, and the River Indus; for the return route, the
mouth of the Indus, the Persian Gulf, and the valley of the Euphrates.
In the twelfth volume of Grote's "History of Greece"
is an admirable map, showing the whole of the marches of Alexander.
It is not impossible that Russia may anticipate the whole of this
scheme by a railway which, leaving the mouth of the Volga, shall
skirt the northern end of the Caspian, and run southward and eastward
through Tartary and Afghanistan to the Indus. Whichever, Russia
or Great Britain, first reaches the Indus by a railway route will
be the master of India from Ceylon to the Himalayan Mountains.
It must not, however, be understood that the Italian government
had any such extended views in projecting the tunnel through-the
Alps. It proposed simply to facilitate travel between France and
Italy, or rather between its own province of Savoy, lying on the
northern side of the Alps, and the remainder on the southern side
of the mountains.*
* In 1860 the provinces of Savoy and Nice were
ceded by Italy to France, in exchange for portions of Lombardy,
wrested from Austria. The tunnel, which had been commenced by
Italy, was to be completed, under Italian superintendence, at
the joint cost of France and Italy. As the map now exists, the
northern end of the tunnel is in France, the southern in Italy,
the summit of the Alps being the boundary between the two countries.
The Alpsusing the term in its widest senseis that
remarkable chain of European mountains which forms the water-shed
dividing the rivers which empty into the Mediterranean from those
which fall into the Atlantic, the German Sea, and the Black Sea.
The whole length of the ridge is about 1100 miles, besides numerous
spurs or offshoots, such as the Apennines, the Pyrenees, the Carpathians,
and the Balkan. Generally, however, the term is restricted to
much narrower limits, and denotes that mountain chain which, commencing
near the head of the Gulf of Genoa, curves northward to Mont Blanc,
and thence northeastward through Switzerland, the Grisons, and
the Tyrol in Austria, where it terminates in the Great Glockner,
"Bell Tower." This range, sometimes styled "The
Higher Alps," measures about 420 miles. In parts it consists
of a single steep range; elsewhere, notably in Switzerland, there
are several parallel ranges, scarcely less lofty than the main
ridge. The loftiest peaks are in Switzerland, where, within a
space of not more than sixty miles, are the highest points in
EuropeMont Blanc, the loftiest of all, reaching an elevation
of 15,744 feet above the level of the sea. From this central point
the mountains fall away gradually in either direction. But still
the height of the ridge, not counting the more elevated peaks,
is about 7000 feet. In our sense of the word there are no "passes"that
is, deep depressions cut down through the great mountain wall.
Whoever crosses it must ascend about 7000 feet. Nineteen "passes"
are, indeed, enumerated; but of these eight can only be traversed
by foot passengers, and now and then by mules. Over the remaining
eleven there are carriage roads; but there are not more than five
that are fairly passable for carriages; and for three of these
roads the world is indebted to Napoleon.
The one pass with which we have now to do is that which leads
near but not over Mount Cenis. Near the centre of the great northwestern
curve of the Alpine chair rises Mount Cenis. It is by no means
among the loftiest of the peaks. Its summit is four-fifths of
a mile lower than that of Mont Blanc, and it is overtopped by
nearly a score of other peaks. Still it dominates over all its
immediate neighbors, rising to an altitude of 11,454 feet-nearly
twice that of any point in the United States east of the Rocky
Mountains. From the peak the summit of the chain sinks down northward
into a long col, or "neck," the lowest point of which
is 6672 feet highabout 400 feet higher than the summit of
Mount Washington. This neck is what is styled the Pass of Mount
This possible pass from Gaul to Italy appears to have been
unknown to the ancients. Hannibal, two centuries before Christ,
went directly past it, for forty miles, crossing the Alps at the
Little Saint Bernard, losing on the way 33,000 out of the 59,000
men with whom be started. The first authentic mention of the Mount
Cenis pass is a thousand years later, when (about A.D. 755) Pepin
led his army across it, to aid the Pope against the Lombard king.
Half a century later his son Charlemagne led another army, for
the same purpose, over the same route. To this day there stands,
almost at the summit, a hospice, said to have been founded by
Charlemagne. In 1557 the Duke of Alva led his Spanish army over
this pass for the subjugation of the revolt in the Netherlands.
A century later Marshal Catinat led a French army into Italy over
this pass. During these centuries the roadway had been somewhat
improved, but it remained little better than a mere mule-path
until 1803, when Napoleon conceived the idea of making a carriage
road over the pass, to form a means of communication between France
and Italy, then united under his sceptre. The work, occupied seven
years, and was the most marvelous engineering achievement hitherto
accomplished. It was a highway, eighteen feet broad, excavated
for a great part of the distance in the sides of the mountain.
Taking its two proper terminal points, San Michel on the western
side, and Susa on the eastern, the distance in a straight line
is about thirty miles; but following the windings of the road,
it is fifty. In that space the road ascends and descends about
5000 feet, say a mile of absolute elevation and descent. The mode
of travel was by diligence, sixteen mules being required to drag
a carriage up the steepest ascents. In the winter the carriages
were frequently placed upon runners instead of wheels. More than
half of this perpendicular ascent and descent had to be performed
within what in a straight line would be about eight miles.
For forty years this Napoleonic road seemed the only practicable
way of crossing the Alps at this most available point. But meanwhile
railways had been pushed up to the foot of the mountains on either
side. But no one for years seems to have dreamed that this sharp
ascent, sometimes amounting to a rise of one in twelve, could
be overcome by any engine moved by steam-power. The problem lay
in this shape: the moving power of a locomotive is simply the
amount of the traction of the driving-wheels upon the rails. Upon
a straight course, an ascent of one foot in a hundred produces
a sensible effect; one in fifty is a grade so heavy as to diminish
the effective power of the engine by half. At one in twenty-five
the power is practically nothing; a locomotive train attached
can barely overcome it. A little steeper, and the driving-wheels
will only revolve upon the rails, without moving the locomotive
at all forward. Arise of one in thirty is about the utmost practically
overcome by an engine with a train, even when the rails are perfectly
dry; if they are at all wet, a locomotive alone will hardly climb
the ascent. Now upon the Mount Cenis road there are frequent ascents
of one in twenty, and sometimes those of one in twelve.
half a dozen years no one seemed to imagine that such ascents
could be conquered. But about ten years ago Mr. Fell, an English
engineer, conceived a plan for accomplishing this, and in 1865
obtained a temporary grant from the French and Italian governments
for laying down and working a railway upon the line of Napoleon's
Mount Cenis carriage road. Now that the thing has been accomplished,
it all seems simple enough, and the wonder is that no one should
have thought of it before.* All depends upon an additional centre
rail, laid between the two rails on an ordinary track. This rail
is the usual one; but it is laid down flatwise, so that the two
running faces are presented upon either side. This centre rail,
for reasons which will be apparent, is raised about a foot above
* The general Idea was set forth forty years
ago by Vignolles, a French engineer, and our own Ericsson; but
we- believe it was first put into execution by Mr. Fell on the
Mount Cenis Railway.
The locomotive, besides having the ordinary perpendicular driving-wheels,
is furnished with two pairs of horizontal ones, which can, by
means of a screw and lever, be made to grip the centre rail like
a vice, with any required amount of force. The actual tractive
force of the locomotive is thus more than doubled. Indeed, by
multiplying these wheels, and increasing the force of their grip
upon the central rail, it would be theoretically possible to construct
a locomotive which should draw itself up an absolutely perpendicular
ascent. The limitations of this theoretical power are only the
limits of the tenacity in the metals of which the whole is composed.
There is also,
in addition to the ordinary brake acting upon the wheels of the
carriages, another which acts upon the centre rail. The form of
this is shown in the accompanying cut. The flat face A,
and the corresponding one on the opposite side, usually run smoothly
close to the faces of the rail; but by turning the shaft B
by means of a lever, connected with a handle upon the platform,
the two sides are brought together like the jaws of a vice gripping
the rail on either side. This centre brake alone will bring a
train to a full stop within seventy yards. Combined with the ordinary
wheel-brake, it will bring a train to a pause within less space
than one needs to stop a carriage with the horses at a fair speed.
This centre brake really controls the movement of the trains.
The actual wear and tear upon it shows the work it has to do.
As we found in the journey which we are to describe, it wears
away so that its faces must be renewed at each trip. One other
provision for safety is made upon this road. For each carriage
is provided a deeply-flanged pair of guide-wheels, one running
upon each side of the centre rail. These must prevent the train
from breaking off the rails, even in rounding the sharpest curves.
It is held tight upon the track at so many points that it must
go on the rails.
Looking back upon all which was found evinced by a trip over
the Fell Railroad, it seems to us that safety is secured upon
a route whereof we have not the like for probable danger. We can
not learn that any accident has ever happened on this route. We
think, moreover, that the principle involved in the Fell Railroad
is worthy of earnest consideration by our railway engineers. It
seems to us that a railway constructed upon these principles can
obviate not a few of the great difficulties which our engineers
have to meet. For example, it seems to its that, had we studied
it a few years ago, we should have never undertaken the construction
of the Hoosac Tunnel. At all events, it is certain that herein
is to be found means of reaching many of our mining regions hitherto
supposed inaccessible to railways. We can by it mount ascents,
and round curves steeper and sharper than any with which we have
as yet fairly grappled.
So much by way of preliminary to what we shall have to say
respecting the existing railway over the summit of the Mount Cenis
Pass. Now for the tunnel through the ridge. Rising near Mount
Cenis are two little rivers running in parallel but exactly opposite
directions, upon either side of the ridge. The Arc, upon the French
side, running northward, falls into the Isere, and thence into
the Rhone, emptying into the Mediterranean near Marseilles. The
Dora, upon the Italian side, running southward, falls into the
Po, near Turin, and thence finds its way into the Adriatic. Now
at one point, a score of miles from their source, these two rivers
approach each otherthe Are bending a little to the south,
the Dora to the north. The distance at this point of approach
is about eight miles; the elevation of the valley of the Are being
here about 3700 feet; that of the Dora some 400 feet more, or
3000 below the summit of the pass. But between these two points
the ridge of the Alps stands sentinel and barrier. This rocky
barrier is pierced by the tunnel, 13,577 yards, about seven and
seven-tenth miles; so that in that distance an ascent and descent
of about 3000 feet are saved.
Having mastered all these details, we set out on our special
tour of examination; the time being eighteen months ago, when
no war raged in France. Leaving Paris, and traversing the fertile
plains of Burgundy, passing Dijon and Macon, we climb the gentle
lower slopes of the mountains, and reach the little village of
San Michel, where the ascent of the Alps fairly begins. Here is
the French terminus of the Fell Railway.
The carriages which are to convey us have a familiar look.
They are almost exact counterparts of those of our city railways,
just about as broad, the seats running lengthways along the sides.
By special favor we are allowed to ride on the locomotive, and
thus gain a better view than could be had from the carriage windows.
In a few minutes we get our first view of the difficulties we
have to surmount. The track rung straight up a hill steeper than
any railway line we have ever seen, except the old inclinelong
since abandonedat Schenectady, in New York, or the coal
road at Mount Pisgah, in Pennsylvania. The actual ascent, by measurement,
for half a mile, is one foot in eighteen; but if our eyes can
be trusted it is not much less than the half of a right angle.
But there is nothing in which our senses more deceive us than
the real slope of a mountain-side. Thus, the Peak of Teneriffe,
which to the eye is a perfect sugar-loaf, has an inclination of
only 12 degrees, or one in thirty; and the very steepest face
of Mont Blanc, which looks almost perpendicular, is less than
45 degrees, or one in eight, an inclination only half greater
than some which we shall have to mount on this railway. The centre
rail driving-wheels are screwed up, and the little engine pulls
us up this rise with scarcely an apparent check. Then follows
a comparatively slight ascent for ten miles, the, average rise
being only one in forty-eight. This brings us to Modane Station.
Here, looking across the gorge, we see a thin line of smoke rising
far up the side of a steep mountain. This, we are told, marks
the northern terminus of the tunnel, which we shall visit in a
day or two. In the mean while we must go on to Turin, in order
to obtain a permit to go into the tunnel; for of late it has been
found necessary to exclude visitors, excepting for two days in
the month, neither of which suits our time; and, moreover, we
wish to examine matters more carefully than we could as part of
a crowd on a regular open day.
looking southward, we get a glimpse of the ridge through, or rather
under, which the tunnel is to pass. Following with our eye the
line pointed out to us is, the direction of the tunnel, our vision
is barred by a peak which, we are told, is called the "Grand
Vallon," just midway between the two extremities of the tunnelFourneaux,
where we see the smoke rising, and Bardonnêche, the opposite
terminus on the Italian side. The Grand Vallon, we are told, rises
to an altitude of 11,000 feet, only 454 less than that of Mount
Cenis; and right under the highest point runs the tunnel; so that,
measured in a straight line downward, fully a mile and a half
of Alpine rock, at its highest point, overlies the tunnel. By
rights the tunnel should be named the "Grand Vallon,"
for Mount Cenis is fully a score of miles from the nearest point
of the tunnel. However, we suppose that the namelike that
of 'America" for the New World, which should have been named
"Columbia"is too firmly fixed to be changed.
At Modane our train makes a brief halt to take in water for
the engine, and to see that every thing is in order. Well it may,
for right before us is an ascent steeper than any thing we have
yet seen. It is, by actual measurement, one foot in twelve. So
steep does it look that we can hardly believe that any train can
overcome it. But we go at it with a dash, with the utmost speed
which our little locomotive can accomplish. The screws are put
on the horizontal driving-wheels, and up we go, our speed diminishing
yard by yard, until it is reduced to four miles an hour. We could
fairly out-walk the train. Should any thing give way, we must
go back to Modane and try again; for, although the entire brake
power would be sufficient to hold us fast on the incline, and
prevent us from running back, the train could not be started again
if the brakes were on; and if they were off, we should just slide
down in spite of all the engine could do.
But no accident happens, as we believe none has hitherto happened
here; and we breathe freer as we begin to ascend a gentler inclination.
All the way we have been winding upward along the steep face of
the cliff, upon the outer edge of Napoleon's road, of which our
railway track occupies the outer edge, so that, without any parapet
between us and the abyss below, we can look sheer, down precipices
whose depths seem to us immeasurable. At Termignon the valley
makes a sharp turn to the east, so that we can look back over
the zigzag line by which we have so far ascended. Then comes a
great bend back and forth, and another sharp ascent, by which
in a mile we rise 350 feet.
This brings us to Lans-le-bourg, twenty-five miles from San
Michel, and 2220 feet above that place. Here begins the great
dead-lift of the road, for there is a further ascent of 2240 feet,
which must be accomplished in a space of six miles. Here the engines
are changed, for it is not safe to trust the work to one which
has just been employed in dragging the train from San Michel.
From our station on the locomotive we can mark the zigzags and
curves of the road, which winds around like a huge snake. So sharp
are the curves that our train of five carriages is often bent
like a horse-shoe, the locomotive and the hinder car running in
exactly opposite directions. Nothing but the centre rail and its
appurtenances could prevent us from running off the track, and
plunging sheer down the precipice which we overlook. At every
moment something reminds us of the possible perils of the way.
At intervals of only a quarter of a mile, perched upon some commanding
point, are houses of refugesolid little stone structures
designed as shelters for travelers in the old diligence days (not
very old either, for our railway dates back only five years) who
should chance to be caught in a sudden snow-storm.
Ever and anon we plunge into darkness, for at the most exposed
points the railway forms a covered way, having heavy plank walls,
and a roof of corrugated iron. Two miles out of the six occupied
by the ascent, and as many more upon the opposite descent, are
thus roofed over.
But the summit is at length gained; then comes a run of five
miles of almost level ground, when we begin the tremendous descent
upon the Italian side. The descent is even more wonderful than
the ascent, for it is almost continuous, with hardly an intervening
level stretch. The views which we get are wonderful, changing
every instant. At one moment we look far down over the lovely
valley, dotted over with villages, vineyards, and farms. Then
we turn a curve, and there is before us only a frowning wall of
ragged rock. Again we seem to be literally banging midway between
valley below and peak above. We actually slide down a great
part of the descent of almost twenty miles from the summit to
Susa, the Italian terminus of the Fell Railway. Here, even more
clearly than on the ascent, the value of the centre rail was shown.
The wheel-brakes were not once applied, the centre brake alone
regulating the speed.
which we give, selected from an immense number, show better than
can be done by words some of the most striking features of the
scenery upon the route. At the head of the article is the Echelle
du Diable "Devil's Ladder"a little way down the
Italian slope. This "ladder" is a zigzag, rising tier
over tier, constructed to take the place of a portion of the road
as originally laid out by Napoleon's engineers, but which was
abandoned on account of the avalanches which come down. At the
very foot of the ladder are seen the remains of one or two vehicles
which have broken down; and midway up is seen a diligence, drawn
by twelve horses, toiling up the ascent, while another is shown
mounted upon runners. The railway does not climb the ladder, but
leaves it for the old road of Napoleon, and is protected by a
long line of covered galleries. Fort Essillon is near Modane.
Here the road passes high above the river Arc, whose gorge forms
a natural fosse, surmounted by a fortress, now dismantled, built
by the Sardinians to guard the pass. This fort is on the side
of the gorge opposite the road, with which it is connected by
a light iron bridge, called the "Devil's Bridge." It
looks like a slender thread stretching across the chasm. On the
right side is seen the railroad train toiling up, one of the steepest
ascents. Here is one of the most striking views on the route.
The remaining illustrations tell their own story.
In six hours after leaving San Michel we reach the foot of
the mountain on the opposite side of the Alps, where the Fell
Railway terminates, at the little town of Susa, at the head of
the broad valley of the Po. Thence a ride of thirty miles, accomplished
in an hour, brings us to the gay, bustling city of Turin. Here,
repairing to the office of the "Direzione Tecnica del Traforo
delle Alpi," we present our credentials and receive a permit
to visit the tunnel on an off day; and also a special letter to
Signor Genesio, the local superintendent, which will secure to
us every facility for a thorough examination of the work.
terminus of the tunnel is less readily accessible than the French
one; so we retrace our way to Modane, and walk over and up to
Fourneaux, a little village dug in, as it were, upon the steep
hill-side. A more unpleasant place, filled with less pleasing
people, it would be hard to find. We never before saw so many
people afflicted with that ugly, wen-like excrescence, the goitre,
and its accompaniment, apparent idiocy. But the scenery is magnificent.
Above us rises the Grand Vallon, its upper portion white with
snow; while, lower down, the cliffs are clothed with firs and
pines, looking, in contrast with the snow, almost black. Lower
still are trees and shrubs, whose foliage, clad in bright autumnal
hues, reminds us of what we have seen among our own White Mountains
of New Hampshire. But far higher abovealmost twice higher
than Mount Washingtonare piled the Alpine peaks, soaring
one above another, and shutting, in the vision at either extremity
of the valley.
Here let us gather up what, during a three days' stay, we learn,
by the abundant courtesy of the officials, of the origin and mode
of construction of the tunnel which we are to explore.
The idea of the tunnel appears to have been first broached,
about 1832, by M. Medail, a Piedmontese, born at Bardonnêche,
who pointed out where lay the least thickness of the Alps between
Piedmont and Savoy. Ten years later he presented to the Italian
government a plan for a tunnel through the ridge. Two engineers,
MM. Maus and Sismonda, were thereupon appointed to investigate
the matter. After four years they reported favorably upon the
line which has been adopted. The great difficulty lay not in the
fact that it must run so far beneath the summit of the mountain;
since, for all practical purposes, it made no difference whether
this towered half a mile or five miles above. Either distance
would equally prevent perpendicular shafts from being sunk to
the level of the line, so that the working could be carried on
simultaneously at many points. The mountain could be attacked
only at its opposite sides, from which the two ends of the tunnel,
well-nigh eight miles apart, must be driven toward each other.
Moreover, how were the hundreds of laborers to be supplied with
air, which could only reach them for almost four miles underground?
Again, as far as was then known, only human labor could be employed.
Steam-power was out of the question; for the steam-engine must
have fire, and fire must have abundant air, as well as coal and
water. It now seems strange to us that, with the knowledge then
existing, the work should ever have been seriously considered.
Looking back upon the work done, we may safely say that, by no
means known to man in 1855, could the excavation of this tunnel
have been performed in half a century. Only so many men at a time
could work within the contracted space. Unless some mechanical
means of drilling other than that of steam-power should be devised,
the work, if undertaken, must have been abandoned before it had
been a quarter completed.
But, as it
happened, about 1850, three young Italian engineersSommellier,
Grandis, and Grattoniwere engaged in a series of investigations.
They had no thought of the Mount Cenis Tunnel, with which, however,
their names have come to be inseparably connected. All that they
then thought of was a means of propelling, by means of compressed
air, railway trains up a steep incline among the Apennines. The
idea was to use compressed air as the motive power. The principle
upon which they started was one already well establishedthat
air, when compressed, has a great expansive and elastic power.
This principle is well shown in the toy known as the "air-gun."
The amount of possible force thus to be acquired had long been
settled. Air compressed to one-sixth of its natural state has
an expansive force of about 84 pounds to the square inch. This
is about half more than the pressure of steam in an ordinary stationary
engine, as usually worked.* The merest tyro in mechanics need
not be told that no machinery creates power. Levers and pulleys
and cogs simply enable us to concentrate or apply power already
created at the point where we wish to use it; and this transfer
is always accompanied by more or less loss. But, as it happened,
there was, just where Sommellier and his associates wished to
use this compressed air, a river, which gave abundant force for
compressing the air. The problem now became a purely mechanical
one. It was merely to transfer the water-power of the river into
the shape of condensed air. As we shall see, the same advantage
was to be found at each extremity of the proposed Alpine tunnel.
* We find that the engine which moves the entire
mass of machinery in the establishment where this Magazine is
printed is usually worked at a pressure of from 50 to 60 pounds.
It is safe, however, to increase this by a half.
About 1855 Mr. Bartlett, an English engineer, invented an apparatus
by means of which a drill, driven by steam, was made to perforate
a wall of rock to far greater advantage than the same work could
be done by hand. His idea was mainly the use of his machine in
coal mining in England, where, we believe, it has been and is
used to advantage. But, as we have seen, Bartlett's steam-drill
could not be used in the Alpine tunnel; while the Italian air-engine
was equally unavailable in an English mine, where no water-power
for compressing the air was to be had.
It occurred to Sommellier and his associates that the two inventions
might be combined into one, and used to bore through the Alps.
The result of this is shown in what we shall have to see, and
explain as best we may.
Sommellier and his friends proposed their plan to the Italian
government of their day. How the putting this into execution was
postponed for years, until the troubles connected with the rise
of the new kingdom of Italy got, in a fashion, settled, is a story
too long to be told here. Suffice it to say that finally, under
the administration of Cavour, somewhere about 1857, the Italian
government fairly took upon itself the work of digging the Mount
The first thing was to fix mathematically upon the exact direction
which the tunnel should take, so that the two opposite headings
should meet under the summit of the Great Vallon. In engineering
phrase, the horizontal axis of the tunnel was to be fixed; that
is, a line was to be marked out over the crests right under which,
no matter how far below, the tunnel should run. In fixing this
line the two engineers, Copello and Borelli, to whom the work
was confided, encountered great difficulties. They had to scale
the rocky sides of cliffs, making paths over untrodden regions,
and use their surveying instruments in a region where, at any
moment, a sudden storm might interrupt their work. But it was
at length performed, and from the summit of the Great Vallon,
11,000 feet above the sea, down the slope on either side, a line
was marked out, right under which the tunnel should run. That
the tunnel should nowhere deviate a foot to the right or the left
from following this line, lay fairly within the known limits of
engineering skill. The compass, carefully used, would settle that.
But there was a far more serious difficulty to be met. The two
portions of the tunnel must not only approach each other in the
same direction, east and west, but they should meet at the same
vertical elevation. The precise inclination of the two excavations
must be rectified at every rod; otherwise, when they should have
met at the centre, one might have been yards or rods above or
below, the other. There were not wanting those who, up to the
very last moment, doubted whether the two workings would ever
meet. But the final result, known first on Christmas-day, 1870,
showed how accurately all had, been done. When the last foot of
rock had been broken through, the two excavations struck each
other almost to an inch. The first man who passed through the
dividing rock, we are told, was Grattoni, one of the three of
whom we have spoken. If we could have chosen the proudest three
single moments which could mark a human life, one should have
been that when Napoleon, at Austerlitz, saw the Austrian line
fairly cut in two; another should have been Wellington's, when
he saw Napoleon's Imperial Guard tumbling back in rout from its
charge upon his solid square; the third should have been that
of Grattoni, when, first of all men, he passed through the Alpine
we examine the apparatus for furnishing the compressed air which
is to supply the perforating engine, which we are soon to see
at work. What we see is rather simple. Close down at the edge
of the Arc is a waterwheel, always at work. On the bank above
is a huge tank, upheld by a score or so of iron columns. It looks
like an ordinary gas-holder. Running up to this are a number of
hollow tubes, each opening into the tank by a valve, opening up
into the tank, so that every thing going up can pass, but nothing
can come back. The wheel drives the water up the tube, forcing
the air before it into the tank. When the column of water has
reached the top of the tube a valve at the bottom is closed, cutting
off the water, while another is opened, allowing that which has
entered to pass off; while at the same time another valve at the
top is opened, admitting air into the pipe. Then, when the pipe
has been emptied of water, the escape-valve is closed and the
supply-valve opened, and the rising water again drives the air
before it into the tank; and soon perpetually. All this operation,
so hard to describe, is easy to understand when once seen. The,
current of the river turns the, wheel; the wheel forces up water
into the pipe; this condenses the air contained in the pipe; and
so a force which costs nothing, and which, for untold ages has
lain useless, is made, under human guidance, to work miles away.
At Bardonnêche, the other end of the tunnel, they are able
to dispense with the water-wheel and the whole pumping apparatus.
There, high up on the mountainside, is a stream which never fails.
From this the water is conveyed by pipes into the condensing cylinders,
rising when the supply-valve is opened, and falling when it is
closed. Otherwise all is the same as we see at Fourneaux.
The condensing apparatus at Fourneaux is about half a mile
from the mouth of the tunnel. The condensed air is borne from
the tank through an iron pipe of eight inches in diameter. As
we pass up to the mouth of the tunnel we see this pipe running
along the way. We notice the manner in which it is laid, and are
inclined to think it absurd. At intervals of three or four yards
are low pillars of masonry, upon the top of which is a short piece
of pipe, mounted upon rollers. The intervening pieces are braced
firmly by iron rods let into the upholding masonry.
"What is the use of this?" we ask of our guide.
"The temperature of the valley outside of the tunnel,"
he replies, "often varies fifty degrees in the course of
a single day. Now, if our pipe were here laid in the usual way,
its expansion and contraction under these quick changes of temperature
would soon tear it to pieces. We have to make it practically an
elastic tube. Now see how our plan works. The ends of the fixed
parts, between the pillars, fit into those upon the tops of the
pillars, much as one slide of a telescope runs into another. Now
when our tube expands by heat, the fixed, part is driven a little
into the movable part, resting on the pillars; when the tube contracts
by cold it is pulled a little out. So our pipe is always of the
same length, no matter what may be the expansion or contraction
of its several parts. The parts resting upon rollers are made,
so simply to give free play to the whole. The jointsthere
are hundreds of themare made as nearly air-tight as possible
by means of rubber or leather padding. So nearly air-tight are
they, that the, escape of air by all is hardly appreciable. One
part in sixty is all that is lost in the whole three miles and
more between the reservoir and the place where we are now working.
Fairly inside the tunnel, where the temperature is equable, the
pipes are laid in the usual way. Don't you see?"
We did see, and inwardly resolved that we would not thereafter
take it upon ourselves to pass summary judgment upon any engineering
question which Would come before us in the tunnel. It might be
that the engineers were wiser than we.
The mouth of
the tunnel, which we reach after a walk of half a mile, presents
nothing specially notable. It is a mere hole in a hillside, only
it looked a little larger than any one which we had seensay
the Bergen Tunnel, near New York. It is a simple horseshoe arch,
whereof the height is within a few inches of twenty-five feet,
and the greatest breadth a foot or two more. Wagons, loaded with
all sorts of materials, are going in; others, equally laden, are
coming out. Fairly within, it is the, most dark, damp, and disagreeable
place we ever entered, even where the work is pronounced finished.
There is, indeed, a solid floor over which to walk; a solid wall
of smooth masonry incloses us on both sides. The stones of which
it is constructed, we are told, have been brought from miles away,
for hereabouts there is no rock which the workmen could hew into
shape for such, purpose. Each step the way grows darker. We look
back toward the entrance through which we have come. It grows
smaller and smaller, until at last it is lost to view. Then before,
behind, above, and around is utter darkness, broken only by the
candles which we carry, and a faint gleam from some gas-light
shining like a star in the distance.
Meanwhile our guide was profuse in his explanations. I I The
floor," be said, "looks level; but right in the centre
is a covered way, three or four feet high and broad., It was at
first designed merely as a conduit for water-pipes and the like.
But one dayit was in 1863when we were working through
a rather soft bit of rock, a great fall of rubbish came down,
blocking up the tunnel, and shutting in three-score men who were
working beyond. They gave themselves up for lost, until one, who
had his wits about him, bethought himself of this covered way
of escape, through which all crawled out. Since then nobody is
afraid of being shut up here."
As we proceed still onward the air grows hotter. A thermometer
banging by the wall, which we read by the light of our candle,
indicates a temperature of 800. "Where are we now?"
we ask. "About two miles from the mouth, nearly at the end
of the finished part on our side, and close upon that in course
of excavation, where you can see how the work is done."
Hardly were the words spoken before a gust of smoke dashed
full in our faces.
"They have been letting off a blast; we shall be just
in time to see the work going on."
Hitherto we had been walking along what might have been some
deserted city street. All at once the way narrowed at the sides
and sank down overhead. "Here we are," said our guide,
"at the entrance of the gallery in corso di scavazione; for
we don't bore this big hole through at once. We make it in three
drifts, two side by side, and one at the top; one a bit ahead
of the other. The Italians drive the top drift ahead; we put in
one of our side ones first."
All this was said in such an odd mixture of languages that
we are to this day in doubt as to the nationality of our guide.
If he was English, he had learned little Italian; if he was Italian,
he had learned little English. Could he have been a Yankee who
had strayed from the Alleghanies to the Alps? Once or twice we
thought his speech bewrayed him. But be he who he might, he evidently
understood engineering. We shall hereafter translate his lingua
Italiana into English.
"Why is this?" we ask. "One way of making the
drifts must be better than the other. Why not find out the best
way, and follow it on both sides?"
"It is all plain enough when once you come to understand
it. The Italian month of the tunnel at Bardonnêche had to
be a little more than a hundred feet above ours at Fourneaux;
and even then we had to make our mouth almost four hundred feet
higher than we would have liked to do. You would suppose that
the line should have run straight down from one end to the other.
That would have answered very well for as, but not for our friends
on the opposite side; for, before they had run down half a mile,
they would have been flooded. Water in one way or another is always
coming into the tunnel; and water, you know, won't run up hill.
So, instead of coming down to us, they were obliged to go up a
little, to jet their water run off on their own side. To make
this ascent as slight as possible, they first excavated from the
top. When our ends meet at the bottom the water may ran which
way it pleases. Do you see?"
We saw again, and were still further inwardly assured that
we had yet something to learn in the matter of engineering.
No sooner had we entered the narrow advanced gallery than we
seemed to come into a new world. The temperature was certainly
high, but the air was pure and sweet, acting like balm upon our
lungs, which had been laboring in the sulphurous smoke. This,
as we soon learned was owing to the fresh air which, after having
done its work in the "Affusto," which we were to see,
had to find its way out, driving before it all foul exhalations
toward the mouth of the tunnel.
"Here we are," said our guide, "just about under
the highest point of the Grand Vallon. I suppose there is a mile
and a half of solid rock right over our heads. We are three miles
into the mountain. They are a little further on the other side;
for we met some harder rock than they did, which made us go slower.
And this," he continued, patting a piece of machinery, "is
our affusto, or, as the French call it, affût,
which in English means just 'carriage.' The nine things which
you see pecking away at the hard rock in front are the perforators;
or, as we call them in French, perforatrices'Mademoiselle
Borers.' This is what has done the work of boring into the Alps."
Instructed as to what the affusto has done, we look upon it
with a kind of reverence; though what we see, as shown in our
illustration, is nowise remarkable. Take an ordinary locomotive
engine, remove the furnace and boiler, and you have a fair idea
of it. There are pipes, wheels, and handles in bewildering confusion,
and a score of men, who seem to know what they are about, in all
sorts of attitudes, managing the whole. The one thing which strikes
us as new is the nine rods, looking like the long antenna of a
beetle, from each of which something comes out and in right against
the face of the rock.
"Count the strokes from one of these," said our guide.
Watch in hand, as though we were timing a racer, we count. In
a minute there are just two hundred strokes.
"Each blow," said our guide, "has a force of
two hundred pounds, quite as heavy as are given by a miner with
a sledge-hammer. Did you ever count how many blows a miner will
give in a minute?"
We had seen mining operations enough, but had never thought
of counting the number of blows. We went through the operation
with our cane, as nearly as we could, and found that we made about
twenty strokes in a minute.
"That's about fair," said our guide. "A miner,
with an assistant to handle the drill, will give about twenty
hammer strokes in a minute; but not more than five pairs of workmen
could find room to work here at once. They would give all at once
a hundred blows a minute. Now Madame Affût, with her nine
daughters, the Perforatrices, gives eighteen hundred, quite as
heavy, in the same time. To be sure, the madame and her daughters
want about a score of men to wait upon them. But she and they
manage to strike eighteen hundred blows a minute, while it would
take one hundred and eighty men, with hammer and drill, to do
the same labor, even could they have found space in which to work,
which they couldn't. Don't you see?"
Again we saw, and were abashed.
"Look again," said our guide, with professional enthusiasm,
"and you will see how it all works. Our motive power, as
you know, comes from the water-wheel at Fourneaux, which condenses
the air. Thence it comes up where we are. We have got our power
where we want it, in the affusto. We use it just as though it
were steam. See that cylinder; in it works a piston, to the end
of which is attached a drill. Now, when the air is let on, it
drives the drill against the rock; and when the air is cut off,
back comes the drill. Look again, and you will see that at each
stroke the drill turns around a little. To make this rotatory
movement takes more than half of the machinery which you see;
but it must be done. In handwork one man turns the drill, while
the other gives the blow. Affusto does both; she strikes the blow
and turns the drill. Again, iron striking stone educes fire. We
must put this out as fast as it occurs. So you see that with each
perforatrice is a man, holding what looks like a common garden
hose, through which he throws water into the hole made by the
drill. You see that each perforatrice works independently of all
the rest, so that any change in the movement of one does not affect
the others. Moreover, which you will hardly notice, each has a
flexible joint, so that the drill may be directed up or down,
to the right or the left, as may be required. Ah, there you see;
that drill near the middle has gone deep enough, and they are
going to have it make a new hole."
The drill to which our attention was called was withdrawn,
and put at a point a yard distant. For a minute or two it seemed
to strike "wildly," as pugilists say, as if not knowing
just where it meant to hit. A man with a booked rod guided it
for a little. But as soon as a hole a few inches deep was made,
the drill worked of itself.
"How deep do you drill?" we asked.
"That depends upon the character of the rock. In this,
through which we are now passing, about a yard. In the hard quartz
which we met a while ago, when they got a start of us on the other
side, we went only half as deep; and that was fearfully hard upon
the drills. In ten minutes they got so blunted that we had to
change them. As it is, we wear out about a hundred and fifty drills
and two perforators for every yard we gain. M. Sommelier estimates
that, all told, we shall use up a couple of thousand of the Mademoiselles
Perforatrices before we get through. If we get off with the loss
of that number, it will be less than I expect. The general idea
is to drill about eight hours at a time, and then blast. To clear
away the stone takes about half as long as it does to do the drilling;
so that generally we blast twice a day. A day with us means four-and-twenty
hours; for the work never stops. We work in gangs, eight hours
on and sixteen hours off. Eight working hours out of the twenty-four,
I dare say, seems short time to you; but it has been found to
be as much as men can well do in this atmosphere. We know only
two holidays Christmas and Easter-Sunday."
We had been
advised to wait for a blast, the crowning event of each eight
hours' work. But the continuous "thuds" of the nine
perforatorsthirty to a second, could we have counted themgrew
monotonous. So we strayed down the tunnel to see how the work
was being done. What we saw was just this: where the two or three
drifts had been blasted into one, numbers of half-naked men were
working away to clear off the rubbish and make all smooth.
Our guide did not seem to care much about these investigations.
For a while he left us quite to ourselves. Possibly he had found
some friends in the tunnel. At all events, when we got back to
the head of the gallery he was in great good humor, and altogether
fluent in explanation.
"You are just in time," he said, "to see the
work done. Look at the drillings."
We, looked: and what we saw, and the explanation thereof, are
shown in the two following diagrams. The wall before useight
feet and a few inches high, and a little broaderwas honey-combed
with holes, about fifty in all, apparently placed at random. The
face of a sand-hill inhabited by bank swallows presents an exact
representation of its appearance. But, as we found, and have shown
on the diagrams, these drillings are by no means made at random.
The affusto, having, through a flexible pipe, given a strong
blast of wind into each hole, driving out all the dust, was wheeled
back, and we saw workmen putting up a heavy barricade of thick
oaken plank behind us. Others began putting in the charges of
powder. We noticed that they charged half a dozen or so near the
centre, then stopped; and all went back behind the barricade.
We prudently went with them.
"Why do you not charge all the holes, and fire them off
at once?" we ask.
"Wait a moment, and you will see," we are told.
At the moment the sound of the explosion was heard, and as
soon as the smoke had somewhat cleared away we reentered. There
was a ragged hole a yard deep, and perhaps eighteen inches in
diameter, in the centre of the rocky face.
"You see the rock gives way at the point of least resistance,
and that was where six or eight holes had been bored close together.
Now we shall charge another and larger circuit of holes. The rock
will, of course, again give way toward the weakest pointthat
is, toward this hole which we have already made, enlarging it
to a couple of yards. Then we shall charge the remaining holes,
and all the rock will still be blown inward, leaving a tolerably
even surface all around the space marked out by the perforators."
The working of these blasts is shown in the two diagrams. The
position of the first hole is represented in the cross section.
Its general shape is indicated by the heavy dotted lines in the
longitudinal section. The outline of the entire excavation is
represented by light broken lines. We could not fail to perceive
the economy in power secured by blasting successively, instead
of all at once; and again resolved that we would not undertake
to instruct the Mount Cenis engineers how to do their work. Indeed,
we rather wished that, when the tunnel shall be completed, some
of them would come to us across the Atlantic. We think they could
teach us something.
Afterward, when we considered that it was the River Arc which
had reallythough indirectly, through Sommellier's air-pipedug
through almost four miles of solid Alpine rock, miles from and
hundreds, of feet above its bedand when we called to mind
the superabundance of water-power which we have lost hitherto,
because lying in ravines so deep as to be practically inaccessibleand
when we considered how that wasted water-power might be translated
into compressed air, and so carried far away to places where it
could be utilized-we became convinced that herein, as well as
in the Yell Railway, lay matter worthy of profound consideration.
What form our speculations finally assumed we have not space here
to put down.
We had in six
hours seen the entire working of the operations on the Mount Cenis
Tunnel; for the rock blasted out having been hauled away, the
affusto was wheeled back, and again began its work as before.
It must not be supposed that the work was completed last Christmas-day.
The heads of the advance drifts then met. The tunnel had yet to
be blasted to its full extent; and, moreover, thirty-four miles
of most difficult railway were to be constructed to connect the
tunnel with the French and Italian lines, between which it forms
a link. We have in this paper simply shown what the Mount Cenis
Tunnel really is, giving attention particularly, to the difficulties
involved in its construction. Possibly, before this meets the
eyes of our readers the tunnel will have been opened.
A few facts and figures, by way of memoranda and suggestion,
and we have done: the actual work upon the tunnel was begun in
1859; the air-perforators, without which the whole must have been
a failure, were introduced in 1861. In 1863, Savoy having been
annexed to France, an agreement was made between the French and
Italian governments, in accordance with which Italy was to execute
the whole within ten years, receiving from France about 32,000,000
francs as payment for half of the work, with deductions in case
the completion should be delayed. It is generally understood that
the French payment will fall short of half the total cost, which
is estimated now at 75,000,000 francs, say $15,000,000. But it
should also be borne in mind that this sum means touch more in
Italy than with us. Thus, the payment of ordinary laborers on
the tunnel is three francs a day; with us the same men would command
about two dollars. It is fair to estimate that, measured by our
standard, the cost of the tunnel itself, less than eight miles
long, will be $50,000,000. But this is only a part of the actual
working cost. As we have said, thirty-four miles of railroad have
to be built, and the whole equipped with engines and carriages.
We have before us two estimates of the probable entire cost, which
readers may take for what they are worth, only bearing in mind
that engineers' estimates are usually far short of actual cost.
Captain Tyler, the English Board of Trade inspector, in 1868,
estimated the entire cost at £5,400,000($27,000,000). Sir
Cusack Roney, an eminent British contractor, estimates it at £7,200,000
($36,000,000). Both sums are based upon the price of Italian labor.
We should, in counting the cost, multiply by something more than
three, and so judge that, taking a fair mean between the two estimates,
the whole cost of the Mount Cenis Tunnel and Railway, 42 miles
in all, will not fall short of $100,000,000. That, as a commercial
enterprise, it can ever pay, seems out of the question. And it
may be safely assumed that, as it is the first, so it will be
the last enterprise of the kind which will be undertaken for generations.
But, as we have before intimated, two things, hardly more than
incidental to the whole idea, are worth to the world much more
than all has cost. These two things are: Fell'sor rather,
perhaps, Ericsson'scentre rail and appurtenances, and Sommellier's
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