Monocab Monocab is one of the earliest PRT designs, dating from 1953. It was originally developed by Edward Haltom who was studying
monorail systems. Haltom noticed that the time to start and stop a conventional large monorail train, like those of the
Wuppertal Schwebebahn, meant that a single line could only support between 20 and 40 vehicles an hour. In order to get reasonable passenger movements on such a system, the trains had to be large enough to carry hundreds of passengers (see
headway for a general discussion). This, in turn, demanded large guideways that could support the weight of these large vehicles, driving up capital costs to the point where he considered them unattractive. Haltom turned his attention to developing a system that could operate with shorter timings, thereby allowing the individual cars to be smaller while preserving the same overall route capacity. Smaller cars would mean less weight at any given point, which meant smaller and less expensive guideways. To eliminate the backup at stations, the system used "offline" stations that allowed the mainline traffic to bypass the stopped vehicles. He designed the Monocab system using six-passenger cars suspended on wheels from an overhead guideway. Like most suspended systems, it suffered from the problem of difficult switching arrangements; since the car rode on a rail, switching from one path to another required the rail to be moved, a slow process that limited the possible headways. Two LIMs were used, one on either side of the vehicle, arranged in a unique fashion that acted as both the motors and lift systems. The only other project to consider ROMAG was a much smaller system in Las Vegas that ended when the federal capital funding dried up. In the aftermath of the show, the UMTA started the Advanced Group Rapid Transit (AGRT) program to continue development funding for three of the systems, Boeing, Otis and Rohr. Phase I of the AGRT started in February 1974, with the ROMAG receiving less funding that the others. The Phase II program was to originally end in 1979, but was later extended until 1981. Rohr decided to sell the system to Boeing at this point, a sale that went through on 3 February 1978. ==Notes==