number of different car sizes, seating 6, 12 and 18 passengers. The larger cars could be formed into two-unit trains which could increase system capacity in small loop or shuttle operations, but the two-unit train had limited advantage in large network applications where short headways are effectively an electronic coupling. The "KK" series of vehicles, "KK 3, 6,12,18(all designed, but only the KK 3 and KK 12 were developed), were all of the same cross sectional area with only the length of the vehicle changed. With the same construction style in the body and undercarriages, these vehicle could share the same small vehicle guideway. Motor and power supply In order to provide fine control over vehicle spacing and reduce maintenance costs, the companies selected a linear motor (LIM) for the Cabinentaxi project. Linear motors were a major area of research since the 1960s when they were first introduced in the U.K. by Eric Laithwaite. As they have no moving parts, a LIM-powered vehicle would be more reliable than one using a conventional motor. Another advantage is that there is no contact between the motor and the track, so snow or rain will not affect its performance, which means a LIM vehicle does not require additional headspace in bad weather. Also, because the traction does not rely on friction, LIMs can climb much steeper grades. On the downside, LIMs require a "reaction rail" for the motor to push against, which increases capital costs slightly. Guideway Cabinentaxi was designed to allow top or bottom running of the vehicles, or both on one track. Guidance and control Cabinentaxi's control system was decentralized, with three different control systems, each in command of one portion of the system's overall operation. The vehicle itself was responsible for maintaining separation from the vehicle in front of it, and automatically switching from guideway to guideway. Since the measurement and control of separation did not require communications with external systems, reaction times were greatly reduced and headways were much shorter than systems using a central computer to control spacing. There was a centralized control system used in Cabinentaxi, but it did not have direct control over the vehicles. This system was used to plan the most efficient route when a customer selected a destination and paid for it. The calculated route was then uploaded onto a magnetic stripe on the customer's fare card. The card was then inserted into