Permanent Way Terminology:
Ballast: The material used as an elastic cushion between sleepers and the top of the formation is called ballast.
Cant or Superelevation: On curves, outer rail of the track is raised higher than the inner rail. This difference of level is called Superelevation or cant
Cant deficiency: The difference between the cant necessary for the maximum permissible speed on a curve and actual cant provided.
Cross-level: The relative difference in vertical levels measured at the top of the left and right rails at a given point on the track.
Creep: The longitudinal movement of rails in the track is called Creep.
Deep flange: When the depth of the flange becomes more than 35 mm.
Flange force: Force generated by wheel flange during movement of the wheel on the track.
Formation: the Flat surface of earthwork on embankments or on cuttings for laying railway track is called Formation.
Gauge: The distance between two running edges of the rails.
Gradient: Amount of slope in the longitudinal direction in a railway track is called gradient or grade.
Hollow tyre: Tyre hollowness exceeding 5 mm.
Point & Crossing: Assembly of components which enables the trains to move from one track to other is called Point & Crossing.
Running edge of the rail: The rail edge on which wheel flange contacts the rail.
Sharp flange: Flange worn out in such a way that radius at the tip of flange reduces below 5mm.
Stock rail: Rail of the main line track against which tongue rails fit.
Switch: Stock rail and its respective tongue rail form a switch.
Tongue rail: The tapered rails whose thicker end is known as Heel are fixed to the main track and the thinner end, known as Toe of the switch.
Thin flange: Flange thickness below 16mm.
Throw of the switch: The distance through which the tongue rail moves at the toe of the switch is called throw of a switch. Its value on Indian railway is 114mm.
Twist: The rate of change of variation in cross-level per meter.
The transition of the curve: It is an easement of the curve in which change of degree is uniform.
Wheelbase: The distance between the two adjacent axles of a bogie is called wheelbase.
Wheel gauge: The distance between the inner surface of flanges of left and right wheel mounted on an axle.