It has been found that human sensations are dependent on acceleration, the rate of change of acceleration (impulse) and displacement. In other words, the product of these values could be used as the measure of comfort/discomfort. Riding is a quality of comfort experienced by a passenger, depends not only upon acceleration, the rate of change of acceleration & vibration but also some other factors as like noise, moisture temperature etc.

A ride index is just a number with no units and its value gives us an indication of the riding comfort of a vehicle. The index is easily calculable during field trials by measuring the vertical/lateral accelerations using standard accelerometers.

Ride Index gradations are as follows:


RI criteria applicable on Indian Railways:


The Following Measures Should Be Given to Maintain Ride Index in ICF coach:

by proper checking of primary suspension arrangement :

Checking free height &height variation.

  1. Telescopic hydraulic dashpot & oil level in it (1.6 liters in modified & 1.4 liters in non-modified).
  2. The gap between safety loop & axle box lug should be within the limit.
Proper pairing of springs on secondary suspensions:
  • Free height of spring should be within the limit.
  • Ensuring proper working of the shock absorber.
Proper checking of side bearer, oil & bearing piece should be within limit:
  • Oil quantity should be 2.0 liters.
  • Thickness of bronze piece should not be less than 42 mm
  • Thickness of metal piece should not be less than 8.5 mm [6 mm dia hole is provided at the center of bronze piece for better lubrication/working]
  • Proper checking of silent bushes fitted in bolster for proper matching of the centre pivot.
Proper checking of buffing gears:
  • Proper contact of buffer plunger.
  • Plunger stroke should not be more than 127 mm & less than 51 mm.
  • Wear on rubber pads should be within the limit.
  • All securing bolts & nuts should be properly fitted.
Proper checking of draft gear:
  • Wear on rubber pads / coiled spring should be within the limit.
  • Coupling should be in proper tight position.
  • Other securing nuts, washers, cotters also should be in proper position

There should be proper bushing of anchor links. Checking the silent bushes therein.By checking silent bushes working/clearance of self-alignment double row spherical roller bearing.All break gear pins should be provided with proper brushing.SAB curdle roller should be lubricated.

The piston should be a proper working condition, means piston travel should be uniformly, and it should not be sticky.Berth should be provided with Dunlop cushioning.Dynamo pulley & belt should not be loose.It should also be ensured that there should not be any wheel defect as like flat faces (Not more than 50 mm) deep flange, skidded wheel, sharp flange, thin flange.