system of HO-scale slot cars. The system aimed as far as possible for realism, and therefore the slot was as narrow as possible (about 1/8 in) with brass conductors placed vertically at each side. The vehicles picked up power via a small wheel (called a Gimbal Wheel) on their underside, which was divided into two halves by an insulating flange. At some time in the 1960s this mechanism was replaced by a pair of vertically sprung sliding pickups. These differed from that of electric racing car systems such as the same company's Scalextric, in which the electrical conductors were spaced more widely apart on each side of the guide slot, and were hence more stable. There was a small removable peg at the back of the vehicles to stabilize it when in reverse. Vehicles were controlled by a hand-held controller, which had a thumb-operated speed control plus a rotating reversing switch. The range of vehicles was designed to be complementary to a model railway set, and for instance included a Rolls-Royce Silver Cloud, a Humber Super Snipe, an AEC Routemaster bus, a Shell petrol tanker and a towtruck. The most remarkable vehicle was a Road-Railer, an articulated lorry with a pair of pivoting rear axles, one bearing road wheels and the other rail wheels. The semi-trailer could be remotely uncoupled and then collected by a bogie wagon on the Tri-ang railway system. These could in theory be chained together to compose a train. This vehicle suffered from being underpowered. Vehicles could also be driven aboard a car-carrying wagon in the Tri-ang railway system. The basic track sections contained two slots, though single-slot pieces also existed. They permitted quite complex road layouts, and included a crossroads, a 4-section roundabout, forks to create dual carriageway sections, right-angle junctions, single-track forks to allow lay-bys, and later a crossover from the left to the right track (with a break in the conductors). Railway compatibility was ensured by a level crossing and road/rail interchange pieces. Curves could be built with up to 5 parallel slots. Points were manually operated, although third-party electric point solenoids could be fitted. A range of trackside accessories such as a petrol station and a ferry allowed users to build towns around their systems. At a late stage of the system's life, an attempt was made to update its image and enter the model racing-car market. Racing car bodies were introduced,