Australia still awaits a government decision on a very fast train link between our major cities. Worldwide, the debate continues about the merits of different kinds of very fast train.
Australian trains are plodders. It takes the Indian-Pacific 18½
hours to travel between Sydney and Broken Hill, a distance of
1100 kilometres (at an average speed including stops of 60
kilometres per hour). Even the country's fastest train, the XPT,
takes just over 4 hours to travel from Sydney to Canberra (310
Some people say we should use 'tilt' trains, which are
faster than current Australian trains (but still slow by world
standards) and can use existing tracks (Box 1). But most train enthusiasts know that when it comes to real speed, there are only two contenders: the current crop of 'very fast trains' that have wheels and run on steel tracks; and the more imaginative magnetically levitated trains, which excite the mind but are yet to be tested commercially.
How fast is very fast?
The fastest trains in commercial operation today are the French
train à grande vitesse (TGV), the Japanese shinkansen (or bullet train) and the German InterCity Express (ICE). The TGV routinely travels at 300 kilometres per hour through the French countryside and has been clocked at 515 kilometres per hour in test runs. The bullet train averages 262 kilometres per hour between stations and has recorded 443 kilometres per hour in test runs, while the ICE has a top operational speed of 280 kilometres per hour and has recorded 408 kilometres per hour in trials.
These trains have several things in common:
- They all use electric motors (some very fast trains still
run on diesel, but these are slower than their electric counterparts).
- They all have steel wheels that run on steel tracks.
- They have aerodynamic designs to decrease wind resistance -
in some ways they look like long, thin aeroplanes without wings.
- They all require special lines to achieve their maximum operating speeds in particular, these need to be as straight as possible,
because very fast trains and tight bends don't mix well (Box 1: The centrifugal effect and tilt trains). Nevertheless, these trains can also run on conventional lines at reduced speeds, a great advantage when approaching major urban centres.
Let's look at one of the most successful of these trains, the
TGV, in slightly more detail.
Innovations in the TGV
Many of the innovative aspects of the TGV are in the design and
placement of bogies. Bogies consist of two or more pairs
of wheels, their axles and a connecting frame that supports the
carriages (usually called cars) above. At high speeds, the vibrations produced by contact between the wheels and the rails increase
dramatically. This can cause the bogies to sway from side to side,
which in turn can damage the track and, in severe cases, derail
While developing the TGV, engineers found that increasing the
distance between axles in the bogies could reduce this instability.
In addition, since instability increased with increasing bogie
weight, they moved the electric motors, usually mounted on the
bogies, and suspended them from the bottom of the cars.
Bogie placement was also changed. Conventional train carriages
have two bogies each, one towards each end. In the TGV, cars are
attached to each other semi-permanently, with the front end of
one car and the back end of the next car resting on a common bogie.
In this way, each car effectively uses only one bogie (two halves).
Efforts are continually being made to reduce the overall weight
of the train, largely because the lighter the train, the less
stress there is on the track (therefore lowering maintenance costs).
Reducing the number of bogies saves weight. In addition, new,
lighter materials are used in the construction of the trains.
Even the seats are now made of lightweight carbon fibres, magnesium
and composite materials.
Wheels on tracks or levitated
While the TGV, the bullet train and the ICE all use established
technology electric motors and steel wheels revolutionary technology has produced a high speed train which floats on a magnetic cushion of air above a special track.
The maglev differs radically from its more conventional high-speed cousins. It doesn't have wheels and it doesn't run on a steel track. It doesn't even have an on-board motor. The motor that propels the maglev is in the special track, and the propulsion comes from magnets.
In maglev technology, electromagnets (devices that become magnetic when fed an electric current) are mounted on the train and in the track (usually called a guideway). The electromagnets levitate, guide and propel the train along the guideway (Box 2: How the maglev works).
Maglev vs conventional high speed trains
Maglev technology has several theoretical advantages over conventional high-speed trains. Since there is no wheel-to-track contact, less energy is lost due to friction and the trains create less noise. Maglevs also use less energy to achieve the same speed as conventional very fast trains.
In addition, since the motor is in the guideway rather than
on the train, it is possible to increase its power on steep sections. This means that maglevs can climb steeper grades than conventional high-speed trains, reducing the need for tunnels.
Despite such advantages, maglevs remain commercially unproven.
In comparison, trains like the TGV, the bullet train and the ICE
have been formidably successful. Millions of people have travelled
on them; hundreds of thousands use them each day. Each new generation of train gets faster, and they boast an impressive safety record.
One of the biggest barriers to maglevs is the need for a whole
new infrastructure. Their guideways need to be constructed from
scratch, a costly and financially risky venture, at least in the
early stages. In contrast, conventional high-speed trains can
run on existing tracks through urban areas, and the high-speed
portions can be constructed in stages.
Safety of very fast trains
Very fast trains are safe compared to most other forms of motorised
transport. For example, the TGV, which commenced operation in
1981, travels about 10 million passenger kilometres each year.
It is yet to have an on-board fatality, although a number of people
have died in collisions at road crossings.
But this is not to say that major disasters are impossible. In
June 1998, an InterCity Express, travelling at about 200
kilometres per hour, derailed near Eschede in Germany, killing
102 people and injuring hundreds more. The cause of the accident
is still under investigation.
The future of high speed trains
Commentators seem to agree that very fast trains the conventional
ones, at least will form a significant part of the international
transportation scene in coming decades.
But Australia is something of a special case. With our small population dispersed in relatively small towns and middle-sized cities across vast distances, the commercial viability of very fast trains remains in doubt. There is no shortage of ideas: some people talk of a high-speed train network linking Melbourne to Brisbane (via Canberra), and another, linking Melbourne and Darwin, has also been proposed.
Are we on the cusp of a transport revolution in Australia, or
are our trains destined to remain plodders? Should we launch straight into technology, or should we consider the tried-and-true alternatives? Expect the debate to continue, full steam ahead.
1. The centrifugal effect and tilt trains
2. How the maglev works
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