Abstract: A guided vehicle transportation system is described in the application. The system includes guard wheels and a guard rail positioned along a center line of a guide track. The guard rail has a groove in which the guard wheels are received with a predetermined clearance between the periphery of the guard wheels and side walls of the groove. The guard rail has a flange extending toward the groove at the top of each side wall. The vehicle has first arms extending in longitudinal direction and being attached rotatably at a central part of an axle provided for suspending each pair of front wheels and rear wheels, and the guard wheels are attached rotatably and directly to the both end parts of the first arms or attached rotatably to both end parts of second arms each of which is attached to a corresponding end part of the first arms.

Abstract: Structure of a bifurcation site and crossover site of a guideway in a guided vehicle transportation system; in which the guideway consists of left and right roadbeds, a depression between the roadbeds, and a guard rail having a U-shaped groove laid down on the depression; and a fail-safe mechanism is constituted by the guard rail and guard wheels attached to the vehicle; is proposed. The vehicle is equipped with automatic steering mechanisms for steering front and rear wheels and guard wheels supported laterally rotatably by front and rear supporting arms which are supported laterally rotatably underside the vehicle. The guard wheels are received in the groove of the guard rail.

Abstract: Structure of a bifurcation site and crossover site of a guideway in a guided vehicle transportation system; in which the guideway consists of left and right roadbeds, a depression between the roadbeds, and a guard rail having a U-shaped groove laid down on the depression; and a fail-safe mechanism is constituted by the guard rail and guard wheels attached to the vehicle; is proposed. The vehicle is equipped with automatic steering mechanisms for steering front and rear wheels and guard wheels supported laterally rotatably by front and rear supporting arms which are supported laterally rot at ably underside the vehicle. The guard wheels are received in the groove of the guard rail.

Abstract: A guided vehicle transportation system is provided with which toppling down of the vehicle is prevented even when strong lateral external force exerts on the vehicle. The fail-safe mechanism of the system is composed such that a guard rail 31 having a flange 34 extending horizontally at the upper part of each of its vertical guide surfaces for guiding guard wheels 22, 23 provided to the vehicle is laid down on a guide track 3 (depression 10) along the center lone thereof, the vehicle is provided with automatic steering mechanisms 09 and actuators 06 for steering front and rear traveling wheels, and said guard wheels are provided to the vehicle rotatable in a lateral plane and received in the groove of the guard rail 31. A subsidiary guard wheel 33, which is smaller in diameter than that of the guard wheel 22(23), is provided thereon to be rotatable together with the guard wheel 22(23).