In the freight sector, the specific advantages of rail are ideally exploited
by long trains transporting heavy low-value mass goods from point A to point B.
The specific advantages of road transport are best realised by small high-value
goods that have to be transported in small quantities.
During the last decades, the latter type of freight has constantly increased
while mass goods have lost importance. For smaller amounts of cargo the
conventional production system in railways has been the one illustrated in
solution 1 of Figure 1. This system is cost and time-consuming since the
individual units have to be coupled and decoupled in shunting points and often
have to wait until enough units have gathered in order to form a long train on
the main relation. These problems are one of the reasons why the modal split has
changed in favour of road transport.
Figure 1: Customer needs and how they are met by different production
systems
Source: IZT (based on Frederich, Lege 1996)
The most obvious solution to this problem is to make freight trains more
truck-like, i.e. replace long loco-hauled trains by smaller units with a high
degree of modularity and flexibility (due to rapid automatic coupling and
decoupling etc.).
These shorter units can be realised in different ways:
- Short conventional loco-hauled freight trains
- CargoSprinter consisting of multiple platforms, the end ones of each group
are powered by a small diesel motor. The intermediate platforms are unpowered.
Several of these trains can be linked together and run in MU (multiple unit)
configuration.
- Individual self propelled freight cars: Each wagon is powered and runs
independently (usually requiring driverless operation).
The following refers to self-propelled freight cars since they are the most
radical realisation of the concept of modular and flexible freight trains.
Self-propelled freight cars have a propulsion unit on-board. This can be
realised by electric or diesel traction, the latter being cheaper and better
suited to freight traffic running frequently on non-electrified tracks.
Self-propelled freight cars could be used for a direct point-to-point delivery
of small freight quantities. From an economic point of view, this can
economically only be realised by driverless operation. This requires
- autonomous navigation
- automatic avoidance of conflict with other vehicles (replace security
control procedure based on fixed railroad sections and visual signalling by
telematics applications)
- new shunting methods due to application of telematics and self-powered
waggons
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