Personal Rapid Transit in New Zealand - Future Transit Now

The problem of precise longitudinal control of vehicles so that they follow predetermined time-varying speeds and positions has been solved. To control vehicles to the required close headway of at least 0.5 sec, the control philosophy is different from but no less rigorous than that of railroad practice. The preferred control strategy is one that could be called an "asynchronous point follower." Such a strategy requires no clock synchronization, is flexible in all unusual conditions, permits the maximum possible throughput, requires a minimum of maneuvering and uses a minimum of software. Since wayside zone controllers have in their memory exactly the same maneuver equations as the on-board computers, accurate safety monitoring is practical. The paper discusses the functions of vehicle control; the control of station, merge, and diverge zones; and central control.

Courses of Study for Engineers preparing to work on PRT Design.

Covers

• Systems Engineering applied to PRT Systems
• The Simulation and Control of PRT Systems
• The Design of a PRT System

A comprehensive method for calculating and measuring Dependability of Personal Rapid
Transit systems is derived and compared with the more common measure called Availability. Availability is the percentage of all revenue trips that are completed without interruption. It does not take into account the duration of delays of the passengers because of the difficulty of gathering the necessary information in conventional transit systems.

In PRT systems, vehicle-hours of travel and of delay relate in a statistically simple way to personhours of travel and of delay. Therefore, in such systems, it is practical to use the performance measure called Dependability that takes into account the inconvenience of people as a result of delays. To form a bridge to present practice, it is recommended that both measures be calculated and compared in forthcoming PRT systems. With today's computer systems, this is easily accomplished.

To achieve safe and reliable operation at small headways in an optimized PRT system, it is necessary to perform careful failure modes and effects analysis and to follow the recommendations thereby discovered. A major recommendation is that the on-board and wayside computers be dual redundant. In this paper, possible failure modes are analyzed, the mean times between major failures including collisions are estimated, and a series of recommended design features is given. An important conclusion is that, by use of the features recommended, the distance traveled in PRT between incidents that may lead to collisions will be about 10 trillion times longer that in the U. S. automobile system

A system consists of a variety of components that work together to accomplish a specific purpose.  Each type of component in the system has an acquisition cost that increases with its reliability, i.e. the greater the reliability required of a component the more one will have to pay for it.  With increased reliability, the component will not have to be serviced or replaced as often, so the cost of its support decreases with reliability.   The sum of the amortized acquisition cost, i.e., the annual payment for the component, and the annual support cost is the life-cycle cost (LCC).  Since the former increases with reliability and the later decreases with reliability the LCC plotted as the ordinate against reliability as the abscissa is a curve with a single minimum point.