Locomotive traction force

Traction force of a locomotive - the force realized by the locomotive and serving to move the train .

Actually, two locomotive traction forces are distinguished - tangent and on the coupling device ( automatic coupler or screw harness ). The tangential traction force is formed at the point of contact of the driving wheels and rails , and the sum of all these forces is the tangential traction force of the locomotive ^[1] . The traction force on the hitch is less than the tangent, since in this case the resistance to movement from the locomotive itself as a wagon is also taken into account.

Traction force plays an important role in traction calculations , as it largely determines the maximum allowable weight of a train . Its greatest value is required when starting the train, acceleration, and also when following the ascent. At the same time, this force has a number of limitations. In the zone of low speeds there is a limitation on the adhesion force, the excess of which can lead to boxing . In this case, the maximum traction force depends on the grip weight (direct relationship) and on the speed of movement (inverse relationship). In the high-speed zone, there is already a restriction on the power of the primary source (steam boiler for steam locomotives , diesel for diesel locomotives ), as well as the hourly current of traction motors and the temperature of the hydraulic fluid.

Limitations on the maximum traction force are determined by a number of special practical tests, less often - by calculations. Based on them, for each series of locomotives, the estimated traction force is set . In addition, for locomotives with traction motors, hourly and continuous traction forces are set.