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A MODERN SWISS LOCO on the St Gothard run. The overhead catenary supply is 15kVAC at 16.6Hz but the traction
motors are 3-phase, driven by solid state inverters. For a description of this drive system, see the previous episode in
this series.
THE EVOLUTION OF
ELECTRIC RAILWAYS
Swiss railways have always been
innovative, both in their use of tunnels
and electrification and in their electric
locomotive technology. They were also
among the first to employ rack railways,
for use in their mountainous terrain.
By BRYAN MAHER
For 140 years, Switzerland led
the field in hard rock railway tunneling. While other countries were
still contemplating railways, Swiss
trains were running through long
mountain tunnels.
Swiss engineers build the world's
best railways in terrain which
would daunt a mountain goat. Their
complex structures allow an electrified main line to gain 100 metres
of height in a ground distance of
500 metres, without overly steep
gradients.
Saint Gothard Tunnel
For at least 800 years travellers
have crossed the southern Swiss
Alps by the Saint Gothard Pass, a
2134m high saddle-back depression
in the icy mountains, to reach Italy.
The modern steep winding road
through the pass leads from Zurich
and the Swiss plateau to the Po
valley in Italy.
To avoid the difficult road many
international travellers take the
train, burrowing through the mountain via the Saint Gothard railway
tunnel.
PT.23: SWISS TUNNELS AND RACKS
102
SILICON CHIP
1882
a
Locomotive vapeur D 4/4
puissance 950 CV
remorque 170-200 t
17 km/h
~
····•..a-M
a
1917
········...
a
Locomotive vapeur C 5/6
puissance 1580 CV
remorque 335 t
18 km/h
~
a
1920
Locomotive electrique Ce 6/8
puissance 2200 CV
remorque 450 I
35 km/h
a
,..
1955
Locomotive electrique Ae 6/6
puissance 6000 CV
remorque 650 t
75 km/h
················-
a
1975
Locomotive electrique Re 6/6
puissance 10 600 CV
remorque 800 t
a 80 km/h
·-----. ~~;:;-;
<
THIS DIAGRAM SHOWS how increasingly powerful locomotives have been able to pull trains at progressively higher
speeds on the steep approaches to the St Gothard tunnel over the years. The power designation CV for the various
locos refers to Cheval-Vapeur, the metric equivalent to horsepower, equal to 935.5 watts.
Tunnel construction
First proposed by engineer Gottlieb Koller in 1852, the St Gothard
tunnel was initially referred to a
9-state committee formed on 19
August, 1853. Discussions over tunnel construction raged for 20 years.
On 6th December, 1871 the company 'Compagnie du Chemin de fer
du Saint Gothard' was formed to
bore the tunnel and build the
railway. Work started in 1872.
Conditions were terrible. The
continuous uplifting of the Alps
causes high temperatures, water
rushes and rock splintering deep
within the mountain. The difficult
tunnel construction caused the illness and death of many workers.
Of the 2500 workers employed,
mostly Italian, 177 were killed and
400 were hospitalised due to the
atrocious working conditions.
On 29th February, 1880 the northern and southern working parties
met in the middle of the mountain.
Where they met, the centrelines of
the tunnel bores differed by only
50mm vertically and 330mm
transversely; an incredibly good
result for the engineering standards of the time.
The first run through the tunnel
was on Christmas Eve 1881 by a
AN INTERNATIONAL EXPRESS train pulled by a 10,400 horsepower Swiss Re
6/6 locomotive negotiates the helical tunnels on the St Gothard route.
0-8-0 steam locomotive weighing 55
tonnes. Full service between the
towns of Goschenen at the tunnel's
northern portal and Airola at the
southern exit commenced the next
year. How long would an equivalent
railway project take today? Much
longer, we suspect.
Completing the approach ramps
up to the main tunnel are 64 avalanche galleries and smaller tunnels.
To gain height in a short distance,
seven of them are helixes (or
spirals).
These complex constructions
keep the ruling grade down to 2.8%
and protect the track from avalanches and rockslides.
Though double track working
through the main tunnel was
achieved in 1883, the difficult access ramps worked single track until June 1893.
The first Zurich-Milan steam
SEPTEMBER1989
103
es which are the most powerful
single unit locos in the world. These
race their BOO-tonne trains up the
ramps at 80km/h, then at 125km/h
through the tunnel.
Of the 713 mainline electric
locomotives owned today by CFF,
the largest are used on the Saint
Gothard section.
Modern freight trains of 1600
tonnes use two Re6/6 locos, one at
the head and a second about one
third of the way down the train
length. Trains are marshalled with
470 tonnes of freight wagons between the two locomotives, and 1130
tonnes of wagons following the second loco. With so much power
available, Swiss freight trains are
scheduled to run at passenger express speeds.
Communications
THE SWISS HAVE SOME of the most spectacular railways in the world, both
for their scenery and their steep gradients. This is the Zermatt to Gornergrat
rack railway, with the Matterhorn in the background. The electric supply is
3-phase AC via twin catenary wires which feed divided pantographs.
trains weighing 170 tonnes ran at a
stately 17km/h up the steep ramps.
On the easier grade approaching
the 1151-metre high summit in midtunnel, 44km/h was possible.
Electrification
As far back as 1904 the Swiss
were experimenting with a variety
of electric locomotives. One AC loco
was driven by DC motors supplied
by an onboard AC/DC rotary
converter.
Eventually, the St Gothard tunnel
104
SILICON CHIP
was electrified in September 1920
using single phase 7.5kV AC at
16.6Hz.
Articulated ''crocodile'' electric
locos were tops in those days. Rated
at 1.6 megawatts, they could haul
450-tonne trains at 35km/h while
ascending the ramps and achieve
75km/h in the tunnel.
Today, with the St Gothard
system absorbed into the Swiss
Federal Railways, CFF, international expresses are pulled by the
120-tonne 7.BMW Re6/6 locomotiv-
By 1964 the original telephone
system had been replaced by radio
telephone and teletype. This maintains communication between
ground controllers and drivers of
moving trains throughout the tunnel
section. Enormous problems are incurred in such radio links. Transmission and reception is difficult in
a tunnel anyway and is compounded by the interference generated by
the high voltage overhead wiring
and the large commutated traction
motors.
After further upgrading of the
radio system in 1981, controllers at
Goschenen and Airola can independently identify running trains
within the tunnel. In an emergency
the ground controller can bring any
designated train to a halt without
driver response.
Results
In the first three months of 1882,
27,500 passengers and 3000 tonnes
of freight were carried through the
tunnel, assuring the project's success. Annual passenger patronage
has grown from 250,000 in 1883 to
7,000,000 a century later.
Nett freight consigned has increased from 1.5 million tonnes in
1883 to 28 million tonnes in 1980. A
1-day record attained on 25 July,
1979 was 109,950 tonnes.
The number of trains passing
through the tunnel per day has increased from 20 in June 1882 to 310
JUNGFRAUJOCH, INSIDE THE SUMMIT of a mountain, is the highest railway station in Europe, at 3454 metres
above sea level. Note the rack between the rails. Rack and pinion drive is the only way to ensure traction on really
steep gradients.
ENORMOUS AMOUNTS OF HEAVY freight moves along the mountainous St
Gothard route. This train is devoted to heavy trucks. Why can't we have the
same system in Australia, for freight between capital cities?
today. Sometimes only two minutes
separates following trains. At any
time up to four trains will be racing
through the tunnel.
Simplon tunnel
The next very large engineering
project undertaken in Switzerland
was the Simplon tunnel to provide a
short route from France and
western Switzerland to Italy. The
first Simplon tunnel was begun in
1898 and opened for traffic on 25
January, 1906. (This subsequently
prompted the building of the ambitious Bern-Lotschberg-Simplon
system which was described in the
May 1988 issue of SILICON CHIP).
At the time it was the world's
longest railway tunnel. High above
is the freezing mountain pass over
which Hannibal marched his
troops, elephants and horses in 218
BC.
For expediency the 19.8km tunnel was bored single track. The contractors, Brandt and Brandau of
Hamburg, Germany added a
parallel smaller pilot tunnel for
ventilation and spoil transport. Interconnecting the main and pilot
tunnels are transverse galleries
spaced at 200 metre intervals.
The 4000 workers had to endure
terrible conditions, not the least being air temperatures of up to 53°C,
caused by hot springs.
After completion of the Simplon
tunnel, traffic problems were compounded by heavy grades on the approach ramps and by the tunnel being single track. With the opening
of the Lotschberg tunnel in 1913,
more trains came direct from the
Swiss capital Bern and western
Germany. In effect, the Simplon
tunnel became a bottleneck.
SEPTEMBER 1989
105
WHILE SWISS LOCOMOTIVES probably would not win prizes for beauty, they
are right up among the winners when it comes to sheer power. This 20 year
old Re4/4 weighs only 80 tonnes but is rated at 4.7MW (6320hp). It has a top
speed of 140km/h.
To provide double track running,
enlargement of the original parallel
pilot tunnel, to be called Simplon II,
was begun in 1912. This was interrupted by the 1914-18 war and was
not completed until 1923. Electrification was not completed until
1930. Since then, many improvements have been made to the tunnel
wiring to allow faster running.
Now, trains race through the tunnel at 140km/h, with speeds of
160km/h planned for the near
future.
Tourist tunnels
In Switzerland there are many
privately owned and operated
railways. These companies cater
for the thousands of tourists and ski
buffs wanting transport to otherwise very inaccessible places.
106
SILICON CHIP
Adjacent to the 4166m high
Jungfrau mountain in the Bernese
Alps was a centuries-old hospice on
the peak of Jungfraujoch. When fire
destroyed the ancient building in
1972, the construction of a new
modern tourist hotel was hampered
by the severe climate. During the
day, temperatures vary between
+ 7°C and - 30°C. In addition, blizzards at 250km/h are common, with
15 metres of snow falling annually.
The rebuilding, transport of
materials and influx of tourists carried on despite the weather, using
the Jungfrau private railway. This
unique line has few problems with
snow and ice because most of its
track is in tunnels inside the Eiger
mountain. One of the railway stations halfway up inside that infamous mountain was featured in
the movie "The Eiger Sanction".
Built in 1910, the Jungfrau line
connects with the CFF system at Interlaken, then heads for the high
country, to Jungfraujoch, 3454
metres above sea level, the highest
railway station in Europe. This station is hewn from solid rock, inside
and almost at the summit of Jungfraujoch Mountain. The highest
9.3km of this railway includes 7km
of tunnels and the track gradient on
the steepest slope is 1 in 4.
Rack and pinion drive
Since normal wheel adhesion is
impossible on such grades, the
Jungfrau line uses a rack-andpinion drive.
Interestingly, the Jungfraujoch
railway is one of the remaining five
in the world still using a 3-phase
supply. It was built that way right
from the start and uses 650V AC at
40Hz. This was the local industrial
supply.
Twin overhead catenary wires
THIS VIEW IS OF another privately run rack railway in the Swiss mountain countryside. How is this train powered,
since the pantographs are down? Did they stop for lunch? Note that narrow gauge track and rack drive.
and divided pantographs are used
to feed the train, with the third
phase connection being via the
wheels and rails.
When trains are negotiating
track intersections, one section of
the pantograph must not meet the
wrong overhead wire for fear of
short circuits. Should both pantograph sections touch wrong
overhead wires, the train would be
instantly reversed.
Overhead wiring construction at
track points and crossovers must
prevent any possibility of such accidents. The designs used to fulfill
this condition are truly ingenious.
Branches of this line take tourists
to Murren, on the western side of
Jungfrau mountain. Also served is
Grindewalde, near the Wetterhorn
and the 4030m high Mount
Schreckhorn.
Zermatt Gornergrat railway
Since 1898 there has been a
railway system taking sightseers to
the top of Mt Gornergrat in the Pen-
nine Alps. It attracts tourists from
all over the world, eager for a closeup view of the breathtaking
scenery.
From the lookout on Mt Gornergrat, at over 4000 metres elevation,
visitors have a breathtaking view of
the roof of Europe. Only 5.4km to
the south is the 4633m high
Dufourspitze de Monte Rosa, the
highest point in Switzerland. Just
13km to the west is The Matterhorn, 4477m high, regarded by
many as the wonder of the world.
To the north, a mere 7km distant,
are 4203m Mt Rimpfischhorn and
4207m Mt Alphubel.
The Zermatt to Mt Gornergrat
railway has been continually
upgraded and modernised to provide safe and comfortable transport. Hugging the cliffs or bridging
the ravines, this 9.35km line
ascends the mountain to the terminal station 3089 metres above
sea level.
Again on grades of 20% or more,
adhesion traction is an impossibili-
ty and so an ABT type rack-andpinion drive is used. Two-car
trainsets are employed, driven by
eight motors each rated at 300kW.
The overhead supply is again 40Hz
3-phase at 550VAC.
On such heavy grades brake
design is critical. Dynamic braking
is standard and available at all
speeds, even during power supply
failures. Disk brakes are also provided for emergencies.
Passengers come to Brig via the
CFF or BLS main lines, then take
the narrow gauge train up the
Nikolai Valley. Passing close to the
4512m high Mt Weisshorn, the
train climbs the foothills to Zermatt
where the rack railway is joined.
From Zermatt to the top of
Gornergrat mountain, the demand
is such that on this rack railway
trains run every 12 minutes.
Acknowledgement
The author thanks CFF for information, photos, drawings and permission to publish.
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SEPTEMBER 1989
107
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