Abstract: In a vehicle guidance system, a circular-section guidance rail is embraced y a detector on a vehicle. At a fork, where the rail progressively broadens prior to dividing, the rail height is reduced so that a detector, when tilted to select one branch of the fork, has its lowered side between the rail and a side wall of a channel in which the rail is mounted and its raised side riding over the broadened rail.

Abstract: A steering system for a guided vehicle comprises a coupling device for coing the steering axle actuating linkage both to a detector for guiding the vehicle along a guidance reference member and to a steering gear, the coupling device comprising first and second elements respectively mechanically linked to the steering gear and the detector and mounted for movement along first and second guide bars, each element being movable between first and second positions on its guide bar, the guide bars being so coupled to the actuating linkage that an element in the first position transmits movement to the actuating linkage and in the second position is ineffective to transmit such movement.