Five innovations that could shape the future of rail travel
Introduction What will the future of public
transport look like? The major projects being planned today, such as the UK’s
HS2 high-speed rail network, aren’t fundamentally different to what’s
been built over the last 30 years. Maglev trains are largely confined to niche
projects in China. Hyperloop remains an unproven glimmer in Elon Musk and
Richard Branson’s eyes.
The likes of HS2 can deliver considerable improvements
in network capacity through incremental changes in conventional designs,
from tracks to train bogies. Yet while the rail sector is warily slow at
introducing new technologies due to the long time it takes to plan and build
new lines and vehicles, there are a number of technical innovations in
development that, if adopted, could make the trains of tomorrow both faster and
A Switch or points failure is
responsible for nearly 20% of the total delay experienced by
passengers on UK railways. This occurs when there’s a problem with the
mechanism that enables trains to move from one track to another at a junction.
Despite the frequency of the problem, the technology used in these mechanisms
has hardly changed since the first design nearly 200 years ago.
But a collaborative research project has
explored radical alternative technologies. For example, one innovative
design called Repoint has three independent motors that can lift and
shift the rails, relying on gravity to lock them back into place and providing
redundancy in case one or two of the motors fail.
contrasts with existing switches that slide the rails sideways. They can get
stuck midway so have costly additional layers of sensors and protocols to
mitigate the risk. The next-generation “mechatronic”
switches aim to work faster, improve ease of maintenance and reduce
the risk of failure through their backup motors.
B Conventional suspension systems restrict a train’s
speed as it travels on curved track, limiting how many trains you can run on a
route. These suspension systems essentially work like large springs,
automatically changing the distance between the wheels and the carriage as the
train travels over uneven ground to make the ride feel smoother.
Active suspension systems are now being developed
which introduce new sensors, actuators and controllers to more precisely alter
the distance between wheels and carriage. This offers improved ride
comfort and enables the train to travel round curves with greater
speed and stability. This can be combined with systems to actively tilt
the train as it rounds the corner, offering increased benefits.
C In a conventional wheelset, both wheels are
interlocked and connected with a fixed axle, preventing any relative rotation
between them. When a train enters a curve or a divergent route at a junction,
it must slow down to ensure the wheels are guided over the track and to prevent
unwanted vibration of the wheels. Railway researchers are now
developing independently rotating wheels to include a separate actuation mechanism that can help steer the wheelsets on the
D High-speed electric trains need to maintain good
contact with the overhead power lines via the pantograph that sits on top of
the vehicle. On the UK mainline, pantograph height usually varies by about
2m to secure the connection in different areas such as in tunnels, level
crossings and bridges.
Researchers are starting to develop active
pantographs that have their height and the induced vibration involved in
power transfer controlled by an actuator. These active pantographs can improve
the contact force and eliminate contact loss problems due to rapid changes in
the overhead line height and other environmental disturbances such as wind.
E The number of trains that can run on a route (and so
the capacity of the line) depends in part on the signalling system. Most
railways use a fixed-block system, which divides the tracks into sections. Only
one train at a time can be in each section so there has to be a significant gap
between the trains.
But some railways are now starting to use
a moving-block signalling system, which determines the necessary gap
between trains based on the distance it takes for them to come to a stop in an
emergency. But this gap could be reduced further if it’s based on real-time
information about what the train in front is doing and where it will stop if it
hits the brakes.
This is known as “virtual coupling” and involves the
two trains communicating information about their changing speed and brake
activity so that they can decrease or increase the gap between them to the
minimum necessary. With shorter gaps between them, more trains could run
safely on a route, increasing overall network capacity.
Conclusion With such innovations, we could introduce trains that
are able to adapt to the changing characteristics of the line in order to
maintain high speeds throughout most of the journey and avoid those annoying
stop-start periods of travel. Widening and disrupting the boundaries of current
railway designs in this way would enable us to create a next-generation network
with a step-change in performance that is fit for the 21st century – without
any need for expensive levitating trains or vacuum tubes.
Source: The Conversation. Author: Saikat Dutta