Affordable Dual-Mode Vehicles and Systems


Palle R Jensen, RUF International

Mr. Goltermann raises some very interesting questions in his article of July 15.

Many of them question the cost of a Dual-Mode vehicle. The main argument is, that if you duplicate systems, the cost will be too high.

Let me try to shed some light on why I have chosen the solutions used in RUF.

I have chosen not to duplicate the motor, but to use the same motor both for the guideway and for road driving. I use 2 electric motors in order to avoid a differential, but I could do with one plus a differential, if it turns out to be cheaper.

Mr. Goltermann recommends a look at MagneMotion’s web site. I have done that, and read that LSM efficiency can be expected to be around 50% (85% in larger systems). A modern electric motor can do better than that.

Another important aspect regarding motors is the fact that a change of drive system when going from rail to road (or opposite) represents a possible malfunction. Will the motor start when the car leaves the guideway? If not, the system has a problem. It is safer to use the same drive system for both situations. In ruf, the road wheels always rotate with the correct speed when the ruf leaves the guideway, since the rail drive wheels and the road wheels are connected on each side.

The cost of a system is mainly a question about the cost of the guideway. In RUF much is being done to make the guideway as simple and as slender as possible. Mr. Goltermann suggests the use the road wheels on the guideway. This means that the guideway has to be at least 2 m wide. In order to carry vehicles, the height has to be approximately 1 m. This represents a problem both for the cost and for the visual impact. Both factors can prevent a system from being built. In RUF, the guideway is triangular. The width is only 85 cm. The height of the upper part is 58 cm. The 20 m long modules underneath makes the total height approx. 1 m.

Mr. Goltermann states that any Dual-Mode system should be designed with the difficult task of implementation in mind from the onset. I completely agree with this statement and for RUF, I have proposed the following implementation strategy:

Start with a small system based upon public vehicles. It could be a connector system between parking lots and Major Activity Centers. It could be in an amusement park. It could be as a PRT system.

Expand the system as a public transport system combining Dial-a-ruf service at street level with Automated People Mover service on the guideway network. Door-to-door public transport makes a lot of sense.

Start selling privately owned vehicles for use on the same guideway system.

Connect cities with RUF guideways

Implement freight containers.

Mr. Goltermann is rather pessimistic about the reaction among car manufacturers.

My experience is more optimistic. I have been meeting with car manufacturers. They are absolutely willing to produce vehicles to an operator who pays for a number of initial vehicles for the start system. Once the starting system is running and the congestion problems keep increasing, I think the car manufacturers will recognize that there is a new market here which is interesting. It will be relatively easy to sell a vehicle which can assure the driver a fast and predictable commuter trip. Furthermore the commuter time can be used constructively. The ruf is connected to the Internet with a fast connection via the guideway.

The first rufs may be expensive, but the benefits for the users are also high. To avoid congestion is very attractive. The cost of congestion in Los Angeles is 12.4 billion dollars per year. The cost of a total RUF network covering LA is approximately 10 billion dollars. Electric cars are expensive for two reasons: 1) They are not yet mass-produced. 2) They need 3 times larger batteries than a ruf.

The design of a ruf can be just as attractive as a normal car. The appearance need not be radically different from a normal car. Nothing has to be mounted on the top of the vehicle and the slot under the vehicle can, if needed, be covered when it drives on the normal roads.

I don’t see any major obstacles that will prevent the success of the RUF dual-mode approach.

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Last modified: August 13, 2002