In some regions or countries, there are major public transport routes in which the demand for travel is not predictable or
consistent enough to be connected by rail tracks. While relying on public road transport is not economical either. There are
areas with significant population that do not have adequate capital to install electric overhead cables for some segments
of the city roads (for trolley buses) or rail tracks.
passengers need services without changing vehicles to travel to certain destinations. Such services need vehicles that can
operate under different kinds of route conditions. Another benefit that such vehicles can provide is that operators can save
as much energy as possible under budget constraints due to the costs of the electric power supply. Currently, there are two
kinds of dual – mode vehicles, which are the following:
Dual – propulsion
This is a vehicle that can run on power from two different
sources, which are overhead cables or ground supply that provide electric power and an internal combustion engine. Currently,
there are a number of buses and trains that are dual – mode. Some famous examples include the diesel locomotives that
operate in the underground tracks in Manhattan, New York City, where the
use of diesel engines is prohibited. So, the locomotives must be able to use electricity from the ground power supply. Note
that dual – mode vehicles are different from hybrid vehicles, where dual – mode vehicles use electric power from
one source during operation.
The use of dual – mode propulsion vehicles enables cities or suburban areas to reduce emission figures significantly
while only being able to electrify certain route segments. Dual – mode buses can operate in routes that provide overhead
electric power supply, thus using electric mode, and in highways by using their internal combustion engines. Such buses are
some of the most practical modes of transport linking city centers and airports.
For trains, it is not a new technology, since railway companies such as the former British Rail have used such locomotives,
called electro – diesels, since 1962. However, it is one of the very few railway companies in the world to adopt it
since many countries either have a wide network of electrified rail tracks or only several kilometers of them. Therefore,
they are operated only on routes where trains can operate on electric mode and must also run on many kilometers of non –
Dual – mode
For routes where the demand for travel is not predictable
enough to be provided with rail tracks, vehicles that can run on existing public roads and rail tracks are needed. Thus, passengers
traveling on such routes do not need to change vehicles to their final destinations.
Certain railway companies have conducted research and testing on this vehicle. One company to be used as an example
is Japan Railways (JR) Hokkaido, which are currently performing studies to develop a dual – mode vehicle
concept that can run on roads and tracks.
|JR Hokkaido DMV
In the form of a minibus, it is equipped with a set of steel wheels that can be deployed automatically for running on rail
tracks. Slip lanes of only several metres must be provided in the stations for guiding the vehicles to the tracks or roads,
enabling the vehicle to switch from road to track between 10 and 15 seconds. When running on tracks, only the front steel
wheels have contact with the tracks, not the front tire wheels. While both the rear steel wheels and the inner tire wheels
to make contact with the tracks, enabling the power drive to be sent to the rear tire wheels, similar to a rear – wheel
drive bus. The braking is sent primarily to the tire wheels that still contact the tracks to give more effective braking and
less braking time compared to that of conventional trains. This enhanced grip can cut regular stopping distance by more than
50 %, making the vehicle able to avoid railway collision.
With an estimated cost of around US$ 145,000, its price is 1/7 of a diesel – powered railcar. It will
cost about a half of that of a car and a quarter of that of a train, per seat. Its fuel cost is about a quarter and maintenance
cost about 1/8 of the diesel railcar.
Its implementation, as well a similar concept designed in Britain called the Bladerunner, can
also benefit rural areas greatly since such vehicles can also run on old tracks, thus reviving those tracks. Rural areas will
have the opportunity to offer this service to attract the passing travelers without congesting the rural roads as well as
the highways. This can improve the rural areas’ mobility to the main cities, thus enhancing their economy. The DMV in
Japan is planned to start test commercial operations in April 2007 along
the Kushiro Line in eastern Hokkaido.