The unusual rubber tire tramway in Nancy is actually more akin to a double-articulated trolleybus using a single guide rail in the city center. The TVR is guided by a central rail, on which rollers (two per axle) rest. These rollers exert a pressure of 750 kilograms on the rail, which has several negative consequences such as rails and rollers are very stressed, it produces a reduction in the weight of the TVR (poorer grip) and in tight bend the first roller may escape when travelling faster than walking speed. ? An object inserted in the channel of the rail, such as a bolt or a stone, causes the guides to derail. The front guide wheel rises on the object, even if it is crushed. Rubbish, stones, bolts… are a major problem with TVR. |