A new interior design for rail vehicles is intended to improve
the safety of passengers. And new materials also offer improved
crash protection. Scientists at the TU Berlin have developed an
energy-absorbent plastic which can be injected into the coupling
and buffers between rail-carriages. This is more efficient in
absorbing energy than the shock absorbers of a motor vehicle.
If a tram driver has to stand on the brakes, then the passengers
may well find themselves jerked off their seats. Although seat-belts,
air-bags and ABS braking systems are standard on motor vehicles,
little has as yet been undertaken to ensure the safety of passengers
in rail vehicles. This is the goal of scientists working on a
number of different research projects at the Technische Universität
Berlin. In addition to developing active safety systems such as
brakes and signals, work is also going on to improve the design
of rail vehicles, as a way of improving their passive safety.
Padding, lap-belts and shoulder belts, or improved deformation
zones are tested for their effectiveness by means of computer
simulations and passenger safety tests. "If we know how the
energy can be distributed in the event of a frontal crash"
explained researcher Steffen Sohr, "then we can test for
suitable materials which are able to soak up the forces involved."
The goal is to absorb the deformation energy within a fraction
of a second after a collision, and distribute this without harming
"For example, we can construct the couplings between carriages
so that these absorb energy in the event of a collision and damp
the forces involved." Scientists are testing elastomers which
have very special properties. If it is put on a surface it will
slowly spread out flat. "But if I hit it with my fist, the
elastomer absorbs the deformation energy and springs back to its
original shape;" explains Steffen Sohr. This elastomer can
be filled in the metal buffer sections. Due to the lattice of
bonds between the molecules and the electrostatic forces attracting
them, "this special buffer absorbs more energy than the shock
absorber on a motor vehicle".
Such energy-absorbing systems can significantly improve passenger
safety in trams, but are not effective when it comes to protecting
passengers in high-speed trains.
"By means of a special computer simulation program, I can
try out various seating arrangements and see which is best at
softening the effects of collisions on passengers", added
Steffen Sohr. In addition to the seating position, the actual
seats themselves can have an affect on the outcome of a collision.
Thicker upholstery, and spring-mounted foot-rests and back-rests
can help to decelerate the passenger gently and reduce the risk
The results of this research work have already generated interest
among manufacturers, as one example in Berlin illustrates: The
new series of underground and urban railway carriages being built
in Berlin will include the elastomer filled couplings. And politicians
specialising in transport have also recently called for seat-belts
to be made compulsory in all trains following a tragic rail accident
in Brühl, Germany, in which eight passengers were killed
and 148 were injured.
Contact: Steffen Sohr and Prof. Markus Hecht, Technical
University Berlin, Institute for Road and Rail Traffic
Special field: Rail vehicle technology
Research project: "Passive Safety and Designing Safe Interiors
for Rail Vehicles"
Address: Salzufer 17 - 19, 10587 Berlin, Germany,
Tel: +49 30 314-22444. E-mail: Steffen.Sohr@tu-berlin.de,
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