Traktions

Traktions is a term used in engineering to describe the ability of a vehicle to convert power into forward motion through wheel–surface grip. In road vehicles, it refers to the traction between tires and the road; in rail transport, it refers to the propulsion system that delivers drive power to the rails. Traction is governed by friction, weight distribution, tire condition, and driving inputs, and is limited by the available adhesion between wheel and contact surface.

On roads, traction enables acceleration, braking, and cornering. The maximum usable traction is roughly the product of the normal force (dependent on vehicle weight) and the coefficient of friction between tire and surface. Factors reducing traction include wet, icy, or uneven surfaces, temperature, tire wear, and studded tires. Wheel slip occurs when engine torque or braking force exceeds available traction; modern vehicles use traction control systems to limit slip by reducing engine power or applying selective braking.

In railways, traction denotes the propulsion arrangement: electric traction uses overhead lines or third rails to feed traction motors in locomotives or electric multiple units; diesel traction uses a diesel engine driving electric generators or hydraulic motors. Modern electric traction can employ asynchronous or synchronous motors with regenerative braking and power electronics. Traction performance depends on supply voltage/current, motor ratings, wheel-rail adhesion, and weight on drivers. Pantographs, substations, and wheel-rail interfaces are critical components.

Traction control systems monitor wheel speed and adjust torque to prevent slip, complementing anti-lock braking systems. The coefficient of friction and normal force provide a quantitative estimate of available traction, while vehicle dynamics and road or rail conditions determine real-world performance.