Saturday, April 4, 2009

Dream Taxi

Cabinentaxi (English spelling often given as Cabintaxi) was a German urban transit development project, undertaken by the joint venture of Mannesmann Demag and MBB under a program of the German Bundesministerium für Bildung und Forschung (BMFT, the German Ministry of Research and Development).[1] It had several operating modes, and was accepted as a technically successful trial of some of the concepts of personal rapid transit (PRT).


BMFT had many transportation technology development efforts underway in this period, and the Cabintaxi program was by far the most extensive urban transit program that it managed[citation needed]. Significant within the transportation development programs of the BMFT was the direct involvement of the VOV (German Association of Public Transit Operators), the Deutsche Bundesbahn (German Federal Railway) and their safety experts. This assured that when system development was completed, the systems would meet German (and by extension international) public transit standards.
System design

While the core elements of the Cabintaxi system were based around the concepts of PRT, for example with vehicle sparations of 1.9 seconds, the system's design scope was broader with the intention of offering more urban application potential.
While Cabintaxi offered full PRT (small-vehicle origin-to-destination) routing, the joint venture partners recognized the difficulty of starting a PRT project without phasing, and that larger vehicles would allow greater market acceptance and more practical initial applications. For this reason, larger capacity vehicles were developed. These vehicles could operate as single units, or "married pairs" (two independent vehicles coupled to be considered one two car unit) of two 12-passenger vehicles (24 passenger units) and two 18-passenger vehicles (36 passenger units.) The higher capacity vehicles were seen as allowing greater initial capacity in areas with limited route coverage. Married pairs of higher capacity vehicles allow for higher capacity simple shuttle applications. Simulations showed that for route operations, married pairs reduced system flexibility and added little if anything in capacity for systems that could operate at under three second headways. The 12 and 18 passenger vehicles had the same width and height as the PRT versions, and could operate over the same small profile guideway. These systems were designed for seated passengers only.
For the seated passenger systems, there were three variants, one with vehicles running above the guideway, one below the guideway, and a combination where vehicles traveled both over and under the guideway. The over and under variation doubled route capacity while reducing the overall passenger trip time and the amount of elevated structure needed to serve a given geographic area when compared to the single level vehicle approaches. All were based on common components in a modular guideway/vehicle design.
A more robust guideway option was provided with standing passenger vehicles intended for more conventional transit or institutional service. This system called, Cabinlift, allowed standing passenger vehicles, operated above or underneath the guideway, but did not provide a combination over and under system option as the Cabintaxi technology.

Cabintaxi technology logged over 400,000 vehicle-miles between 1975 and 1978 at their test track in Hagen, Germany. In 1977 the system completed fleet operation endurance testing of 7500 continuous vehicle hours - and again in 1978 of 10,000 continuous vehicle hours. The fleet was made up of a maximum of 24 operating vehicles over two levels. These are the only PRT fleet endurance test of these magnitudes ever carried out successfully with vehicle separations under 3 seconds.
The development program was considered successful by the German Government and its safety authorities and in 1979 was authorized for urban transit applications in German cities.
Hamburg and Detroit projects

A system was proposed for Hamburg, initially consisting of approximately 7.5 miles of over and under guideway with 11 stations and 50 vehicles. The total costs for this initial installation was estimated by the Hamburg Hochbahn in 1977 to be $56,568,000 or $7.5 million per double lane mile. These were not the final system costs which would have only been determined after construction, and cost increases were already being experienced as the project neared the start of construction.
Cabintaxi was also considered one of the leading contenders for the US Downtown People Mover Program, and was widely recognized as the favorite system to win the Detroit People Mover Project. For the Detroit project, the system's over-and-under beam was a major advantage as the City of Detroit specified a single beam system, and the Cabintaxi system was the only competitor capable of bi-directional operation on a single beam.
The schedules for the Detroit People Mover Program and the Hamburg application appeared to conflict, so the consortium chose to withdraw from the US competition and concentrate on Hamburg. This withdrawal aggravated officials of the German government, as the system had been developed with expectation that it would be a significant export product[citation needed]. It coincided with a request by the American government for increased defense spending by the NATO allies, which resulted in a funding cut to all other departments of the German government. BMFT withdrew funding for the Hamburg project with a statement that among other things[citation needed], the failure to pursue the export market — specifically Detroit, and the mandated budget cuts, led to its decision.
The developing firms found themselves without a market opportunity in Europe or the United States, and withdrew from the public transit field. The United States firm of Cabintaxi Corporation obtained the technology shortly after the development team withdrew from the field.