WHERE THE SNOW-PLOUGH WORKS IN SUMMER
The Scandinavian peninsula has been the battle-ground of many titanic
struggles on behalf of the railway. In this country the iron horse
has forced its way to the most northerly point in the world where the
shriek of a locomotive whistle may be heard. This is Ofoten, a port on
the Atlantic seaboard of Norway, beyond the 68th parallel, and well
into the Arctic circle, where the famous iron mines of Gellivare in
Sweden find a western point for shipping the ore.
It was in Sweden that steel was pressed into service for the first
time in connection with the erection of bridges by the late Major C.
Adelsköld, R.E., and Member of the Academy of Sciences. This was so
far back as 1866, and the daring engineer designed, superintended the
preparation of the metal, and also the erection of the bridge. The
claim of being the first steel bridge has been advanced on behalf of
other structures in different parts of the world, but the records are
against all such statements, for they were anticipated by a decade at
least in a convincing, practical manner.
Major Adelsköld’s bridge is highly interesting, not only from the
historical point of view, but because of its unusual design, and the
methods adopted in its erection. Through the courtesy of Madam Gustafva
Adelsköld, I am enabled to give the following particulars of its
evolution and construction.
The bridge was designed to carry the Uddevalla-Wenersborg-Herljunga
railway across the Huvudnas Falls, just above the Tröllhätten Falls.
At this point the Göta River forces its way through a gorge 137½ feet
wide, just above a fall over a lofty ledge of rock. The depth and
velocity of the water prevented any intermediate pier being erected
in the waterway, so in order to span the gap it was necessary to lift
the girders bodily to set them into position. To enable this end to be
achieved it was imperative that the main girders should be as light
as possible. An iron girder, which was the metal in exclusive vogue
at that time for this work, 153 feet in length by 12 inches wide, of
the requisite strength, would have weighed over 700 tons, and to have
handled such a weight would have demanded expensive and elaborate
erecting tackle.
Major Adelsköld consequently rejected iron as the structural material
in favour of light steel girders. Once these were set he anticipated no
further hindrance to completing the structure as a “suspension bridge.”
Up to this time steel girders never had been employed in such work, and
the engineer, when he revealed his intentions, was urged by experts and
fellow-craftsmen not to use “such a brittle and untrustworthy material”
for so long a span.
Major Adelsköld, however, was convinced of the soundness of his
proposal, and consequently continued his efforts in the face of
spirited opposition. The bridge was built at Bergsund, and the
dimensions were calculated for a strain of 8 tons per square inch,
though the metal was tested to twice that stress before being set in
position. The total weight was only 50 tons.
From the engineering point of view the design is considered somewhat
novel, for it bears no resemblance to the general conception of a
suspension bridge. It is an inverted structure of this class. The upper
members act merely as struts to keep apart the ends of the chains
below, which really carry the load through the medium of the triangular
members.
The method by which the structure was erected was quite as interesting
as the design of the bridge itself. The girders were brought to the
western bank of the river. To swing them into position a derrick was
rigged up on either bank so as to overhang the water. The outer ends
of these masts, which measured 60 feet in length, were fitted with
heavy pulleys, over which ropes were passed and carried from capstans
installed for hauling purposes. The pulley ropes on the eastern bank
were pulled across the waterway and secured to one end of the girder,
while the western bank pulley ropes were secured to the other end of
the steel member, which measured 153 feet in length. In this way the
girder was lifted, swung over the water, and lowered into position. The
event was regarded as so unusual that crowds of people from Gothenburg
and Tröllhätten assembled on the banks to witness the setting of the
steel on February 8, 1866.
Owing to the roar of the waters, the engineer could not make his voice
heard, so orders were communicated across the river in Morse code by
hand-signalling. The first girder was lifted and set in position in
thirty minutes, while the second was handled in half that time. Once
the girders were set it was an easy matter to complete the remainder of
the structure.
It may be interesting to relate that the total cost of setting the
main girders, together with the hire of the tackle borrowed from a
Gothenburg shipbuilding-yard, and including the wages of the men
assisting in the task, was only £25, or $125. At that time Major
Adelsköld’s feat was regarded as an audacious stroke of engineering,
but to-day steel is the exclusive material employed in the erection of
bridges.
Railway-building in these twin countries has been attended always with
grave difficulties, owing to the rugged nature of the country and the
extreme hardness of the rock. When the sea is left, and the interior
plateau is gained, the full brunt of the Arctic weather is experienced,
and it is of a character to deter the most intrepid engineer.
One of the most momentous enterprises that has been carried to
fulfilment in this northern country is the trans-Norwegian railway,
whereby Christiania is brought into direct communication with the
Atlantic seaboard at Bergen. Owing to the prodigious difficulties
involved, however, it occupied some thirty years to carry the scheme
through, although the line is only 306 miles in length.
[Illustration: TRAIN EMERGING FROM REINUNGA TUNNEL, 5,217 FEET LONG, IN
DISTANCE, SHOWING SNOWSCOOP-PLOUGH ON LOCOMOTIVE
WHERE THE SNOWPLOUGH WORKS IN SUMMER]
[Illustration: MYRDAL STATION, SHOWING ENTRANCE TO GRAVEHALS TUNNEL,
17,420 FEET IN LENGTH]
[Illustration: MYRDAL STATION IN WINTER, SHOWING DEPTH OF SNOWFALL
THE BERGEN RAILWAY]
In 1870, commercial interests petitioned for the establishment of
a shorter route between the east coast and the Norwegian capital.
Surveyors, therefore, were deputed to investigate the interior and to
ascertain the practicability of building such a railway. After infinite
labour the engineers reported favourably upon the project, but pointed
out that the work would be unprecedentedly arduous, and would be highly
expensive.
For five years the scheme lay dormant, but in 1875 the Government
decided to commence the enterprise, with a section of line 67½ miles
long, connecting the seaboard at Bergen with Vossevangen. In deference
to views prevailing at the time, however, the narrow- or metre-gauge
was adopted, and in 1883 it was opened for traffic.
Although no further headway was made with the continuation of the main
scheme, it was not abandoned by any means. A mountain barrier, the
Dovrejelf range, barred the way to the interior. Its penetration was
recognised as one demanding great skill, for the peaks are precipitous,
with sides dropping into valleys so narrow as to be mere defiles on the
sea side of the chain. Apart from these physical handicaps, however,
the rain- and snow-falls upon the highest levels were found to be
tremendous, and it was essential that elaborate examination should
be made concerning these adverse influences before the location was
decided definitely.
A cautious policy was practised. No attempt to proceed beyond
Vossevangen was made until the mountain wall had been searched through
and through. No less than twelve alternative routes were prepared and
submitted to the Government. These demonstrated the conclusive fact
that no route could offer avoidance of the snow and rain. The question
was to follow a location, if possible, where these drawbacks were
emphasised to the least degree. For this purpose several meteorological
stations were established among the mountains and on the plateau to
gather exhaustive data by daily observations.
The outcome was the production of some decidedly startling facts, even
to those who were convinced of the extremely inclement conditions
prevailing inland. The observers had been instructed to record
particularly the maximum fall of snow during twenty-four hours, the
depth of the snow among the mountains during the winter, and the
effect of the winds which swept the plateau mercilessly during the
latter season. It was found that snow fell every month during the year
at Fjeldberg, even June, July and August not being free from such
visitations, while at another point the snowfall in winter aggregated
no less than 11 feet. At no point along the projected location of
the line was a depth of less than 8 feet recorded, while the general
average was from 10 feet to 14 feet.
The winds were found to drive the dry, fleecy flakes before them like
dust, to pile up huge drifts in sheltered places, running up to 161
feet deep. Some of these drifts remained throughout the summer, and
were found to be of respectable proportions. The sum of these reports
presaged the fact that, when the line was completed, the question of
maintaining it free from snow-blocks would demand superhuman effort.
At last the Government decided to proceed with the undertaking. The
advantages and disadvantages of the various locations had been weighed
diligently, and promoted the decision to adopt the Gravehals route.
The authorities regarded this location with misgiving in the first
instance, because it involved the piercing of a tunnel 17,420 feet in
length, at an elevation of 2,818 feet. Funds were voted to build the
next section from Vossevangen to Taugevand, a distance of 47 miles.
In this distance the line was to be lifted a matter of 4000 feet to
the highest point to be attained between the Atlantic seaboard and
Christiania.
The route selected comprised the boring of no less than 12 tunnels,
making in the aggregate not less than 11¼ miles, of which the Gravehals
tunnel represented over 3 miles. While this difficult section was being
prosecuted, the Government resolved to come to a definite conclusion
as to the route the railway should follow after attaining the summit
at Taugevand, so as to enable operations to be continued without delay
when the latter point was reached.
The exposed position of the Gravehals tunnel rendered the work
exhausting to the men. As the timber line is about 2000 feet below,
the mountain-sides are quite bare, and there is no protection against
the elements whatever. The work is the longest of its kind in Northern
Europe, and has proved probably one of the most exacting to construct.
It extends through granite which was found to be exceedingly tough, so
that boring was unavoidably slow, especially at times when everything
appeared to be pitted against the contractors.
The firm who accepted the contract undertook to complete the work
for £158,400, or $792,000, which was considered to be a very low
price. It was attacked from both ends, and mechanical boring was
adopted. Convenient water power was harnessed to drive the Brandt rock
drills, which worked under a pressure of some 1,200 pounds per square
inch. Boring proceeded somewhat slowly, more so, in fact, than the
contractors had anticipated; but this was due to the extreme hardness
of the rock encountered, while the work was handicapped by delays which
the contractors could not have controlled. In the first place labour
proved scarce and expensive. The men working on the coast, although
experienced in drilling and blasting rock, could not be persuaded to
proceed up-country to practise their skill. The situation was too
remote, and the elements were too bitter, and seeing that extensive
railway construction was proceeding at the same time in other and more
congenial parts of the country, there was no cogent reason why the men
should hie to an inhospitable locality for work.
The tunnel-borers, however, were spared the tribulations which have
assailed their colleagues in other parts of Europe. Faults in the rock
strata were very few and far between, while subterranean streams and
pockets of viscous mud did not overwhelm them. The temperature within
the boring, moreover, never rose to an intolerable point, the maximum
recorded being 52° Fahrenheit. This was in striking contrast to the
conditions on the Gotthard, Cenis, Simplon, and other central European
tunnels, where the mercury rose at times to the vicinity of 90 degrees.
Yet the workers in the Gravehals tunnel experienced their own peculiar
dangers and exasperating misadventures. The climatic conditions were
the most trying, and many men abandoned their tasks after a short
experience in this bleak situation, for work at a lower level. This
monotony was varied one day by an avalanche, which crashed down the
mountain-side, smashed into the power-house and carried away some of
the machinery. Work had to be suspended for some six weeks while the
damage thus caused was repaired. At another time work could not be
carried forward because no water was available, and about two months
of enforced idleness had to be endured until the turbines could be set
going once more.
On the same section is another heavy piece of work of this character,
the Reinunga tunnel, extending for 5,217 feet through a massive
mountain shoulder. Here the country is extremely wild, and the location
of the line taxed the plotters supremely. The track crawls along a
narrow ledge for some distance, poised nearly 500 feet above the
highroad. The situation is precarious, for landslides and avalanches
are of frequent occurrence, while detached boulders rattle down the
slopes at times and threaten the railway with extinction. Fortunately,
as the metals are laid on a gallery of solid rock hewn in the
mountain-side, the extent of the damage inflicted by these visitations
is limited to the permanent way, though the presence of these untoward
obstacles, and the result of their impact with the metals, may
interrupt communication for a short time.
[Illustration: A VIEW ON THE BERGEN RAILWAY IN WINTER, SHOWING SCREENS
TO PROTECT LINE FROM DRIFTING SNOW, AND SNOWSHEDS]
Seeing that a difference in level of over 4,100 feet has to be
overcome in the 47 miles between Vossevangen and Taugevand, it is
a teasing up-hill pull all the way. The grades are very abrupt at
places, and impose a severe tax upon the locomotives. The passenger,
however, has one compensation for slowness in travel. Some of the
grandest scenery to be seen on the European continent is unfolded
to the train as it glides in and out among the mountain rifts, and
consequently, from the tourist point of view, the route possesses
illimitable attractions, inasmuch as it offers facilities to gain some
of the most beautiful parts of the country, which hitherto have been
unapproachable, except in the face of an arduous and tedious journey by
primitive means of conveyance.
[Illustration: MULES CARRYING WATER IN BARRELS]
[Illustration:
[_See page 279_
LOAD OF RAILWAY METALS ON A MULE’S BACK
RAILWAY BUILDING IN THE ANDES]
After crossing the summit level the railway commences an easy descent,
for the inland plateau is gently undulating, and the valleys being
wider, the surveyors were assisted appreciably in their task of
discovering an easy location. The downward run continues until Bromma,
205 miles west of Bergen, is gained at an altitude of some 450 feet.
Then comes another rise to overcome a low range, which is accomplished
through a tunnel 7,644 feet in length.
This tunnel proved a more exacting and troublesome undertaking than
either the Gravehals or Reinunga works. The boring was attempted
at first on the time system, but the advance was so slow and
unsatisfactory that this principle was abandoned. The whole tunnel was
then handed over to a contractor, but he found the rock so hard that a
piece-work system was instituted. In this arrangement the workmen were
stimulated to supreme effort by the offer of tempting premiums. Issuing
from this tunnel, there is another descent for some miles, when another
ridge intervenes, necessitating a sharp climb of 700 feet, followed
by a smart downward run to Roa, where a junction is effected with the
Norwegian eastern railway system.
Contemporaneously with the building of this line between Vossevangen
and Roa, the original section between Bergen and Vossevangen had to be
overhauled. The metre gauge was in vogue upon this division, whereas
the rest of the line was being built on the standard gauge to secure
uniformity with the other lines. Accordingly, the narrow-gauge was
replaced by standard-gauge track.
The Bergen-Christiania line ranks as one of the most striking pieces
of railway engineering in Europe, and testifies to the remarkable
skill and dogged perseverance of the Scandinavians in breaking down
tremendous obstacles as they arose, with complete success. It is no
light undertaking to attempt such an enterprise as this in such a
latitude across a terribly exposed, storm-swept plateau, among the most
sparsely populated regions of Europe, and where the winter lasts for
eight or nine months. The rainfall is tropical in its severity, while
the storms are of terrific fury, as the workmen found to their cost.
Some idea of the magnitude of the work consummated by the engineers
may be gathered from a few general details. The line passes through no
less than 184 tunnels, which represent an aggregate length of nearly 24
miles. To carry the line across depressions which could not be filled,
14 bridges, ranging from a single-span stone structure of 60 feet to
a metal bridge 566 feet from end to end, had to be built. Between the
two terminal points 55 stations and stopping-places have been provided.
In order to fashion the permanent way the engineers had to excavate
about 35,000,000 cubic feet of earth, and nearly 30,000,000 cubic feet
of rock on the highest parts of the mountain section, this latter task
being assisted by the expenditure of over 1,800,000 pounds of dynamite.
The anticipated task of maintaining communication, especially on the
higher and more exposed sections of the railway, has been appreciated
to the full. To deal with the snow three powerful rotary ploughs have
been acquired, and one is kept in constant readiness. It is no unusual
circumstance for this equipment to be called out in the middle of
summer to cope with a block in one of the deep cuttings. The drift is
a danger against which especial attention has to be devoted, for the
wind catches up the fine, dry flakes and whirls them in clouds across
the country. To prevent this being deposited upon the line, and thus
obstructing traffic, timber screens have been erected beside the line,
this defence continuing in an almost unbroken line for 60 miles between
Mjolfjeld and Gjeilo.
The provision of the line, however, is of far-reaching importance to
the commercial interests of Norway. Formerly, 54 hours were required
to travel between Christiania and Bergen, but now, by cutting almost
straight across the peninsula, the journey can be covered in 14
hours. To forge the link of 215 miles between Vossevangen and Roa, to
complete this undertaking, occupied ten years, and the £3,333,000, or
$16,665,000, expended upon the enterprise is considered an excellent
investment for the country.