Wheel Set (Wheel and Axle)
1. Brief Description :

    The wheel and axle consists of two wheels attached to a small axle, so that these two parts rotate together, in which a force is transferred from one to the other.

    A hinge or bearing supports the axle, allowing rotation. It can amplify force; a small force applied to the periphery of the large wheel can move a larger load attached to the axle.

    The wheel and axle can be viewed as a version of the lever, with a drive force applied tangentially to the perimeter of the wheel and a load force applied to the axle, respectively, that are balanced around the hinge which is the fulcrum.

    The mechanical advantage of the wheel and axle is the ratio of the distances from the fulcrum to the applied loads, or what is the same thing the ratio of the diameter of the wheel and axle. A major application is in wheeled vehicles, in which the wheel and axle are used to reduce friction of the moving vehicle with the ground.

    Fig. 1: Wheel and Axle (Wheel Set)
    Fig. 2: Wheel Set (Wheel and Axle:ICF Coaches)
    Fig. 3: Wheel Set (Wheel and Axle:LHB Coaches)
    Fig. 4: Wheel Set (Wheel and Axle:CASNUB Goods)
    Fig. 5: Nomenclature of Wheel profile parts
    Fig. 6: Showing Nomenclature of Wheel profile parts
2. Details of Wheel Set :

    (a) Wheel Gauge :

      There should be no variation in the values of wheel gauge -measured at fourpoints 90 degrees apart on a wheel set. However, the actual value of the wheelgauge can vary as per tolerances givenMeasurement of Wheel Gauge and recorded duly indicating the following:

      (i) Tightness or slackness of gauge.

      (ii) Whether any indication exists about shifting of wheel on the axle.

      Note: It must be ensured that the back surfaces of wheels are cleaned thoroughlybefore measuring the wheel gauge in order to avoid erroneous readings.

      (iii) If the wheel gauge is more than permissible limit, there exists a possibility ofa relatively newer wheel hitting the nose of crossing.

      (iv) If the wheel gauge is less than minimum value, there is a possibility of wheelhitting at the back of a tongue rail while passing through the switch and thusdamaging the tongue rail.

      (v) Wheel gauge to be checked in no load condition.

      Fig. 7: Location of Measuring Point
      Fig. 8: Wheel Gauge

    (b) Bent Axle :

      A bent axle starts wobbling during motion causing severe vibrations. In order toconfirm whether an axle is bent or not, it must be checked carefully on a sensitivemachine or measuring table.

    (c) Wheel Diameter on Tread :

      Wheel diameter is measured on the tread at a distance of 63.5 mm from the insideface of the wheel. Two measurements 180 degrees apart should be taken foreach wheel.Variation in tread diameter on the same axle as specified is at the time oftyre turning. Effect on safety of any variation beyond this limit should be analysedon case to case basis.

        Fig. 9: Complete Wheel Set
      Video on how Axle fitted to Rail Wheel